Efficient Plant Growth-Promoting (PGP) Native 
The Actinobacteria group of gram-positive bacteria plays an important role in heterogeneous soil systems and is involved in biogeochemical cyclic processes . Densities of soil microorganism distribution, especially Actinomycetes , are highly diverse, ranging from 10% to 50% under abiotic and biotic conditions, because Actinomycete spores actively proliferate under stress conditions and promote soil health improvement . Streptomyces is the predominant organism in the lithosphere and produces economically important active compounds (antibiotics, anti-parasitic, antimicrobial, and immunosuppressive). Actinomycetes contribute to soil health and promote plant growth through the production of auxins and cytokines via various mechanisms . Actinomycetes are unique and significant contributors to plant development and yield increases because, in conjunction with appropriate carrier materials, they may remain in the soil for extended periods and participate in several aspects of plant growth . Actinomycetes have recently received considerable interest as plant growth promoters because of their high antibacterial capability and soil-dominant saprophytic nature . To guarantee that the appropriate amount of an Actinomycete population remains alive for the inoculants to be sustained effectively, it is crucial to ascertain the length of bacterial survival in the corresponding carrier materials. In addition, the chosen carrier materials should be reasonably priced, capable of withstanding adverse environmental conditions, and easily dissolve in water to allow the release of Actinomycetes . Soil carrier materials (peat, coal, and clay) can be classified as plant waste products (compost, soybean meal, and farmyard manure), and inert materials (talcum powder, vermiculite, perlite, alginate, and other inorganic minerals) . Thus, formulations that include one or more beneficial bacterial strains (or species), combined with an affordable and convenient carrier material, have been studied to efficiently distribute bioinoculants to desired crops . Various carrier materials, such as talc, peat, and karnalite, although used in agriculture, are expensive, scarce, and environmentally harmful. Bagasse, sawdust, charcoal, and wood ash are favored microbial inoculants because of their large surface area, moisture retention, affordability, and eco-friendliness. Their capacity to sustain high plant growth-promoting rhizobacterial (PGPR) densities is crucial for effective plant development. The quantity of injected microorganisms significantly affects the effectiveness of microbial inoculation in promoting plant growth. Therefore, ensuring adequate bacterial survival in carriers is vital . Bagasse, sawdust, charcoal, and wood ash, which are affordable and water-soluble, can endure diverse environmental conditions and facilitate bacterial release for sustained inoculation efficacy . Adhesive materials, such as adjuvants like sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB), maintain the bond between microbes and carriers. Charcoal, vermicompost, eggshell powder, and wood ash are preferred owing to their adhesive properties. In addition, the quantity of injected microorganisms significantly influences their effectiveness, necessitating the assessment of bacterial survival in carriers . An Azotobacter chroococcum -based biofertilizer formulation was optimized using different carrier materials by sterilization using autoclave and gamma irradiation for peat moss, a mixture of peat moss and vermiculite 1:2 (w/w), wheat bran, rice husk, clay, and sodium alginate. The results showed locally available low-cost materials to be suitable as carriers capable of adapting bacterial species for a long shelf life . Similarly, rhizobium inoculants were evaluated in a granular formulation using peat as a carrier material for compatibility with physical, chemical, and biological parameters . Commercially produced rhizosphere-efficient strains using cark industry waste residues as a carrier material have been used for the successful production of inoculants without environmental problems and long shelf life . While there are problems with the shelf life of plant growth-promoting organisms in the long term, plant growth-promoting rhizobacteria (PGPR) can enhance plant growth and protect against stresses, maintaining their viability and effectiveness as inoculants over extended storage periods. In the agricultural sector, Actinomycetes are the dominant habitat species of Streptomyces commercially produced for plant growth promotion and are merely free-living soil organisms recognized for their complex interactions with plants and other organisms . Ingredient optimization can be accomplished using charcoal, vermicompost, eggshell powder, SDS and CTAB and wood ash, which have been shown to work best for plant growth Actinomycete inoculants. They can sustain a high density of PGPR and retain their viability because of their wide surface area, excellent moisture-holding capacity, affordability, and environmental friendliness. Therefore, our goal in this study was to compare the sustainability, viability, and suitability of five different carriers for the survival of PGPR isolates at room temperature. Additionally, external parameters such as temperature, moisture, humidity, and CO 2 level were monitored on the Internet of Things (IoT) to investigate the possibility of long-term shelf life of the isolates in various carrier materials during storage. 

Survey and Addressing of Carrier Materials Locally available industrial and domestic waste materials were selected ( and ) for Actinomycete inoculant carrier materials, including wood ash (450 bricks-industry units), charcoal ( Prosopis juliflora occupies 40% of the geographical area in Virudhunagar district), eggshell powder (hostels, restaurants), vermi-cost (Kalasalingam University), and adhesive (resistant to microbial degradation). Carrier material-rich macro (N, P, K, Ca, Mg) and micro (Zn, Cu, Mn, Fe) nutrient natural element resources and slow nutrient release capability of each carrier material with high affinity properties of adhesive will enhance inoculant viability for a long duration and simultaneously induce soil fertility with water-holding capacity . Collection of PGP Actinomycetes Germplasm Plant growth-promoting Actinomycetes were collected from the Agricultural Microbiology Laboratory, Department of Agriculture, Kalasalingam Academy of Research and Education, Krishnankoil, Virudhunagar District, Tamil Nadu, India . Physical, Chemical and Microbial Analysis of Carrier Materials The physical and chemical properties of the collected carrier materials include the pH and electrical conductivity (EC). The pH of the carrier material extract was determined potentiometrically using an ORION ion analyzer with a pH and conductivity electrode . Organic carbon was estimated using a rapid titration method  involving oxidizing the organic matter in carrier materials using a chemical oxidant, typically potassium dichromate (K 2 Cr 2 O 7 ), in the presence of sulfuric acid (H 2 SO 4 ). The reaction releases carbon dioxide (CO 2 ), which is indirectly measured by titrating the remaining dichromate with a reducing agent, such as ferrous ammonium sulfate. The amount of titrant used reflects the amount of organic carbon present in the carrier material and offers a fast and reliable estimate. Available phosphorus was determined using the Olsen method  for carrier materials, particularly under neutral-to-alkaline conditions. In this method, a sodium bicarbonate (NaHCO 3 ) solution (0.5 M) was used as the extractant and the soil sample was shaken with the solution at a pH of 8.5. After the extraction, the phosphorus concentration in the filtrate was determined calorimetrically using the molybdate blue method. Available potassium was determined by the ammonium acetate extractable method using a flame photometer  to extract potassium (K) from the carrier material using 1 N ammonium acetate (NH 4 CH 3 CO 2 ) at a pH of 7.0. The carrier material was mixed with an ammonium acetate solution, shaken, and filtered. The filtrate, which contained the extracted potassium, was analyzed using a flame photometer. In a flame photometer, potassium ions emit light at a wavelength of 766.5 nm in the visible spectrum. These ions are excited in a flame, which enables the quantification of potassium levels in the soil. Typically, 25 ml of 1 N ammonium acetate is used per 5 g of carrier material for extraction, and available nitrogen by the alkaline permanganate method , involves treating the carrier material with an alkaline potassium permanganate solution (KMnO 4 ) under controlled conditions. The solution oxidizes organic matter, releasing ammonium (NH 4 + ), which is then measured as a proxy for available nitrogen. Typically, 0.32% KMnO 4 solution is used, along with sodium hydroxide (NaOH) to create the alkaline medium. The carrier material was heated with the solution, and the evolved ammonia was collected and titrated to determine nitrogen levels. In Vitro Assessment of Actinomycete Isolates for PGP Traits Isolated Actinomycetes , including, Streptomyces rameus (KAC3), Streptomyces bangladeshensis (KAC4), Streptomyces mutabilis (KAC6), Microbacterium arabinogalactanolyticum (KAC8), Streptomyces calvus (KAC10), Streptomyces werraensis (KAC11), and Streptomyces gancidicus (KAC12) were investigated for their PGP properties, such as the production of siderophores, indole acetic acid (IAA), ammonia, mineral solubilization (calcium phosphate), and potassium under in vitro conditions. Solubilization of Phosphate Phosphate solubilization by the isolates was evaluated based on their ability to solubilize inorganic phosphates. Pikovskaya’s agar medium, containing calcium phosphate as the inorganic form of phosphate, was used in the assay. A loopful of Actinomycete isolates were streaked onto plates and incubated at 28°C for 4-5 days. The appearance of a transparent halo around the Actinomycete colony indicated the phosphate-solubilizing activity of Actinomycetes , followed by previously described . Solubilization of Potassium The ability of the isolates to solubilize potassium was tested by spot inoculation of Actinomycete isolates on Aleksandrov medium, as per the method described in previous study , and plates were incubated at 28±2°C for 3–5 days. The formation of a clearance zone around the spots indicates potassium solubilization. Colorimetric Analysis of IAA Production Indole acetic acid (IAA) production was detected as previously described . Actinomycete isolates were grown for 72 h in Actinomyces broth at 30°C. Fully grown cultures were centrifuged at 3,000 × g for 30 min. The supernatant (2 ml) was mixed with 2 drops of orthophosphoric acid and 4 ml of Salkowski reagent (50 ml, 35% perchloric acid, 1 ml 0.5 M Ferric chloride (FeCl3) solution). The development of a pink color indicated IAA production. Siderophore Production Siderophore production was assayed qualitatively using Chrome Azurol S (CAS) blue agar . CAS agar plates were spot inoculated with each Actinomycete isolate, and the development of an orange halo zone around the colonies was recorded as the measurement of siderophore production. Testing Compatibility between Actinomycete Isolates Collected Actinomycete isolates were subjected to an in vitro compatibility assay using the cross-streak method, where each isolate was streaked perpendicularly to other isolates on Actinomycete isolation agar (AIA) medium. All plates, including the control, were incubated at 28°C for 4 days. After incubation, positive results were observed for inter-junction in the merger of Actinomycete growth for compatibility with each other in the plate . Consortium Preparation in Dynamic Media Based on the compatibility test, the active consortia were prepared and designated as C 1 , C 2 , and C 3 in . Initially, a single colony from each Actinomycete isolate was inoculated into Actinomyces broth and incubated at the optimum pH and temperature overnight with continuous shaking (120 rpm). Growth measurements were adjusted based on optical density (OD) at 600 nm. Furthermore, consortia formulations adapted in our laboratory for equivalent amounts of 1,000 μl (10 3 ) of active culture from each isolate were transferred to 100 ml of sterile autoclaved formulation, that is, a low-cost and easily available, nutritional source for bacterial growth (vermi-wash, 50 ml; cow dung slurry, 25 ml; jaggery, 15 ml; black jaggery, 10 ml) and mixed to prepare the individual consortium and incubated at 30°C for 5 days with continuous shaking (120 rpm), followed by previously described . Solid-Based Carrier Bioformulation with Actinomycete Isolates Liquid cultures of the Actinomycete consortium (100 μl) and individual isolates were transferred to 300 ml Actinomyces broth to scale up and constitute an active consortium; 300 ml of the prepared active consortium was centrifuged at 10,000 × g for 10 min. Then, Actinomycete pellets were incorporated with 10 g of 100 g sterilized combined ratio of carrier material (vermi-cost: 50 g; charcoal: 20 g; wood ash: 10 g; eggshell powder: 20 g; adhesive material SDS and CTAB mix in a ratio of 1:1) under aseptic conditions. The mixture was vortexed for 45 min to homogenously mix the carrier material, and the Actinomycete cells were dried at room temperature (28±2°C). After complete drying, the individual and combined-based formulations were packed in clean airtight sterilized packets and sealed separately. The experiments were performed in triplicate. The prepared bioformulations were stored at room temperature 28±2°C and 35±2°C . Shelf Life Assessment of Solid-Based Carrier Material The viability of Actinomycete cultures in the formulation was confirmed by the serial dilution plating method. The formulated product was validated at two different temperatures for incubation under controlled conditions for up to 6-month periods to assess the viability and population status of the Actinomycete isolates. For this purpose, 10 g of packed C 1 , C 2 , and C 3 consortium formulations were prepared, and a 100 ml stock suspension was prepared in a 250 ml conical flask under aseptic conditions. Serial dilutions of the stock suspension were transferred to test tubes up to 10 -6 . The diluted suspensions were transferred to an Actinomycete isolation agar medium using the spread plate method, and the plates were incubated at 28±2°C and 35±2°C. Viability was evaluated initially on the 2 nd and 4 th day. The final CFU/g was calculated as the average of three results obtained from triplicate plate counts . After a predetermined time, the smallest colonies were obtained. As a result, we are able to determine the shelf life or period in which it is best used. Thus, this technique simplifies the determination of the shelf life of a specific biofertilizer sample and provides precise information regarding its application . Digitalized Storage with IoT-Based Monitoring of Physical Parameters The physical parameters of the stored formulated carrier material with the inoculant, as referenced in , were monitored using an IoT device. shows the block diagram of a smart environmental monitoring system using an ESP-32 microcontroller. The system integrates various sensors to monitor environmental parameters and communicate data to the Blynk Cloud for remote monitoring. Each component of a diagram plays a critical role in ensuring that the system functions effectively. The DC power supply provided the necessary electrical power to the ESP-32 microcontroller and all the connected sensors. The ESP-32 microcontroller is the core of the system and is responsible for processing the data collected by the sensors and managing communication with the Blynk Cloud. The Blynk Cloud is a platform that allows the remote monitoring and control of IoT devices. In this system, ESP-32 sends sensor data to the Blynk Cloud via a Wi-Fi connection. Blynk Cloud provides a user-friendly interface accessible from smartphones, tablets, or computers, where users can monitor real-time data, s et al erts, and control devices remotely. The bidirectional arrow between ESP-32 and Blynk Cloud in the diagram indicates that ESP-32 can send data to and receive commands from the cloud platform, enabling a fully interactive system. provides a detailed explanation of each block, its function, and the significance of directional arrows. Statistical Analysis For the experiments, IBM SPSS statistics was used as the statistical software for analysis of variance (ANOVA, version 29.0.2.0), and means were separated using Duncan's multiple range test ( p = 0.05). All experiments were performed in triplicate, and the data are presented as mean values±standard deviation (SD). The correlation coefficients between Actinomycete isolate counts at the two different temperatures were calculated ( p = 0.05). The results were considered statistically significant at the 95% confidence interval ( p = 0.05). 

Locally available industrial and domestic waste materials were selected ( and ) for Actinomycete inoculant carrier materials, including wood ash (450 bricks-industry units), charcoal ( Prosopis juliflora occupies 40% of the geographical area in Virudhunagar district), eggshell powder (hostels, restaurants), vermi-cost (Kalasalingam University), and adhesive (resistant to microbial degradation). Carrier material-rich macro (N, P, K, Ca, Mg) and micro (Zn, Cu, Mn, Fe) nutrient natural element resources and slow nutrient release capability of each carrier material with high affinity properties of adhesive will enhance inoculant viability for a long duration and simultaneously induce soil fertility with water-holding capacity . 

Actinomycetes Germplasm Plant growth-promoting Actinomycetes were collected from the Agricultural Microbiology Laboratory, Department of Agriculture, Kalasalingam Academy of Research and Education, Krishnankoil, Virudhunagar District, Tamil Nadu, India . 

The physical and chemical properties of the collected carrier materials include the pH and electrical conductivity (EC). The pH of the carrier material extract was determined potentiometrically using an ORION ion analyzer with a pH and conductivity electrode . Organic carbon was estimated using a rapid titration method  involving oxidizing the organic matter in carrier materials using a chemical oxidant, typically potassium dichromate (K 2 Cr 2 O 7 ), in the presence of sulfuric acid (H 2 SO 4 ). The reaction releases carbon dioxide (CO 2 ), which is indirectly measured by titrating the remaining dichromate with a reducing agent, such as ferrous ammonium sulfate. The amount of titrant used reflects the amount of organic carbon present in the carrier material and offers a fast and reliable estimate. Available phosphorus was determined using the Olsen method  for carrier materials, particularly under neutral-to-alkaline conditions. In this method, a sodium bicarbonate (NaHCO 3 ) solution (0.5 M) was used as the extractant and the soil sample was shaken with the solution at a pH of 8.5. After the extraction, the phosphorus concentration in the filtrate was determined calorimetrically using the molybdate blue method. Available potassium was determined by the ammonium acetate extractable method using a flame photometer  to extract potassium (K) from the carrier material using 1 N ammonium acetate (NH 4 CH 3 CO 2 ) at a pH of 7.0. The carrier material was mixed with an ammonium acetate solution, shaken, and filtered. The filtrate, which contained the extracted potassium, was analyzed using a flame photometer. In a flame photometer, potassium ions emit light at a wavelength of 766.5 nm in the visible spectrum. These ions are excited in a flame, which enables the quantification of potassium levels in the soil. Typically, 25 ml of 1 N ammonium acetate is used per 5 g of carrier material for extraction, and available nitrogen by the alkaline permanganate method , involves treating the carrier material with an alkaline potassium permanganate solution (KMnO 4 ) under controlled conditions. The solution oxidizes organic matter, releasing ammonium (NH 4 + ), which is then measured as a proxy for available nitrogen. Typically, 0.32% KMnO 4 solution is used, along with sodium hydroxide (NaOH) to create the alkaline medium. The carrier material was heated with the solution, and the evolved ammonia was collected and titrated to determine nitrogen levels. 

Actinomycete Isolates for PGP Traits Isolated Actinomycetes , including, Streptomyces rameus (KAC3), Streptomyces bangladeshensis (KAC4), Streptomyces mutabilis (KAC6), Microbacterium arabinogalactanolyticum (KAC8), Streptomyces calvus (KAC10), Streptomyces werraensis (KAC11), and Streptomyces gancidicus (KAC12) were investigated for their PGP properties, such as the production of siderophores, indole acetic acid (IAA), ammonia, mineral solubilization (calcium phosphate), and potassium under in vitro conditions. 

Phosphate solubilization by the isolates was evaluated based on their ability to solubilize inorganic phosphates. Pikovskaya’s agar medium, containing calcium phosphate as the inorganic form of phosphate, was used in the assay. A loopful of Actinomycete isolates were streaked onto plates and incubated at 28°C for 4-5 days. The appearance of a transparent halo around the Actinomycete colony indicated the phosphate-solubilizing activity of Actinomycetes , followed by previously described . 

The ability of the isolates to solubilize potassium was tested by spot inoculation of Actinomycete isolates on Aleksandrov medium, as per the method described in previous study , and plates were incubated at 28±2°C for 3–5 days. The formation of a clearance zone around the spots indicates potassium solubilization. 

Indole acetic acid (IAA) production was detected as previously described . Actinomycete isolates were grown for 72 h in Actinomyces broth at 30°C. Fully grown cultures were centrifuged at 3,000 × g for 30 min. The supernatant (2 ml) was mixed with 2 drops of orthophosphoric acid and 4 ml of Salkowski reagent (50 ml, 35% perchloric acid, 1 ml 0.5 M Ferric chloride (FeCl3) solution). The development of a pink color indicated IAA production. 

Siderophore production was assayed qualitatively using Chrome Azurol S (CAS) blue agar . CAS agar plates were spot inoculated with each Actinomycete isolate, and the development of an orange halo zone around the colonies was recorded as the measurement of siderophore production. 

Actinomycete Isolates Collected Actinomycete isolates were subjected to an in vitro compatibility assay using the cross-streak method, where each isolate was streaked perpendicularly to other isolates on Actinomycete isolation agar (AIA) medium. All plates, including the control, were incubated at 28°C for 4 days. After incubation, positive results were observed for inter-junction in the merger of Actinomycete growth for compatibility with each other in the plate . 

Based on the compatibility test, the active consortia were prepared and designated as C 1 , C 2 , and C 3 in . Initially, a single colony from each Actinomycete isolate was inoculated into Actinomyces broth and incubated at the optimum pH and temperature overnight with continuous shaking (120 rpm). Growth measurements were adjusted based on optical density (OD) at 600 nm. Furthermore, consortia formulations adapted in our laboratory for equivalent amounts of 1,000 μl (10 3 ) of active culture from each isolate were transferred to 100 ml of sterile autoclaved formulation, that is, a low-cost and easily available, nutritional source for bacterial growth (vermi-wash, 50 ml; cow dung slurry, 25 ml; jaggery, 15 ml; black jaggery, 10 ml) and mixed to prepare the individual consortium and incubated at 30°C for 5 days with continuous shaking (120 rpm), followed by previously described . 

Actinomycete Isolates Liquid cultures of the Actinomycete consortium (100 μl) and individual isolates were transferred to 300 ml Actinomyces broth to scale up and constitute an active consortium; 300 ml of the prepared active consortium was centrifuged at 10,000 × g for 10 min. Then, Actinomycete pellets were incorporated with 10 g of 100 g sterilized combined ratio of carrier material (vermi-cost: 50 g; charcoal: 20 g; wood ash: 10 g; eggshell powder: 20 g; adhesive material SDS and CTAB mix in a ratio of 1:1) under aseptic conditions. The mixture was vortexed for 45 min to homogenously mix the carrier material, and the Actinomycete cells were dried at room temperature (28±2°C). After complete drying, the individual and combined-based formulations were packed in clean airtight sterilized packets and sealed separately. The experiments were performed in triplicate. The prepared bioformulations were stored at room temperature 28±2°C and 35±2°C . 

The viability of Actinomycete cultures in the formulation was confirmed by the serial dilution plating method. The formulated product was validated at two different temperatures for incubation under controlled conditions for up to 6-month periods to assess the viability and population status of the Actinomycete isolates. For this purpose, 10 g of packed C 1 , C 2 , and C 3 consortium formulations were prepared, and a 100 ml stock suspension was prepared in a 250 ml conical flask under aseptic conditions. Serial dilutions of the stock suspension were transferred to test tubes up to 10 -6 . The diluted suspensions were transferred to an Actinomycete isolation agar medium using the spread plate method, and the plates were incubated at 28±2°C and 35±2°C. Viability was evaluated initially on the 2 nd and 4 th day. The final CFU/g was calculated as the average of three results obtained from triplicate plate counts . After a predetermined time, the smallest colonies were obtained. As a result, we are able to determine the shelf life or period in which it is best used. Thus, this technique simplifies the determination of the shelf life of a specific biofertilizer sample and provides precise information regarding its application . 

The physical parameters of the stored formulated carrier material with the inoculant, as referenced in , were monitored using an IoT device. shows the block diagram of a smart environmental monitoring system using an ESP-32 microcontroller. The system integrates various sensors to monitor environmental parameters and communicate data to the Blynk Cloud for remote monitoring. Each component of a diagram plays a critical role in ensuring that the system functions effectively. The DC power supply provided the necessary electrical power to the ESP-32 microcontroller and all the connected sensors. The ESP-32 microcontroller is the core of the system and is responsible for processing the data collected by the sensors and managing communication with the Blynk Cloud. The Blynk Cloud is a platform that allows the remote monitoring and control of IoT devices. In this system, ESP-32 sends sensor data to the Blynk Cloud via a Wi-Fi connection. Blynk Cloud provides a user-friendly interface accessible from smartphones, tablets, or computers, where users can monitor real-time data, s et al erts, and control devices remotely. The bidirectional arrow between ESP-32 and Blynk Cloud in the diagram indicates that ESP-32 can send data to and receive commands from the cloud platform, enabling a fully interactive system. provides a detailed explanation of each block, its function, and the significance of directional arrows. 

For the experiments, IBM SPSS statistics was used as the statistical software for analysis of variance (ANOVA, version 29.0.2.0), and means were separated using Duncan's multiple range test ( p = 0.05). All experiments were performed in triplicate, and the data are presented as mean values±standard deviation (SD). The correlation coefficients between Actinomycete isolate counts at the two different temperatures were calculated ( p = 0.05). The results were considered statistically significant at the 95% confidence interval ( p = 0.05). 

Selection and Characteristics of Carrier Materials presents the characteristics of the different carrier materials and reveals the notable differences in their properties. In that analysis of pH, electrical conductivity (EC), available Nitrogen, Phosphorus and Potassium (NPK) ratio, total carbon content, and carbon-to-nitrogen (C:N) ratios were demonstrated for agricultural applications. Wood ash has high carbon content, a balanced carbon-to-nitrogen ratio, a reasonable amount of nitrogen, phosphorus, and potassium, and is strongly alkaline and salinized. Charcoal has very high salinity and a somewhat acidic pH. It also has very high phosphorus content and low quantities of potassium and nitrogen. Its high carbon-to-nitrogen ratio suggests that it contains a significant amount of carbon compared with nitrogen. Because it is neutral, eggshell powder has low salinity and a high nutrient content. The vermi-cost method has a moderate salinity level, an almost neutral pH, and a relatively low carbon-to-nitrogen ratio. It also offers a fair amount of nitrogen in relation to its potassium and phosphorus content. The surfactants SDS and CTAB, both mildly acidic, lack nutrients, and are used as adhesives. According to the methodology, the solid-based carrier bioformulation process for a unique formulation is very high in the alkaline range but can be adjusted to neutral (pH 6.5 – 7) conditions using lime (CaO). In Vitro Assessment of PGP Traits for Actinomycete Isolates Seven isolates were further screened for PGPR traits ( represents the in vitro assessment of PGP traits), including IAA, siderophore, phosphate, and potassium solubilization. Among them, seven isolates (KAC3, KAC10, KAC11, and KAC12) were positive for IAA, siderophore, phosphate, and potassium solubilization. Among the seven isolates, KAC3, KAC10, and KAC11 showed extensive zone formation for siderophore, phosphate, and potassium solubilization. Among the seven isolates, KAC3 and KAC11 produced IAA with dark-pink color changes in fully grown cultures under laboratory conditions. Isolate KAC12 showed a moderately positive response for the PGP traits. Among the seven isolates screened, three isolates, KAC3, KAC10, and KAC11, exhibited positive responses to all the in vitro PGPR characteristics studied . Compatibility Studies and Consortium Selection Seven Actinomycete species isolated from the soil environment in the Virudhunagar District, Tamil Nadu, were collected. The seven Actinomycete isolates were then used for compatibility assays under laboratory conditions: KAC3 (PP550146), KAC4 (PP177363), KAC6 (PP177364), KAC8 (PP177365), KAC10 (PP177366), KAC11 (PP177374), and KAC12 (PP177389) . The results observed for the two isolates were compatible (KAC8 -KAC11, KAC6 - KAC10 and KAC6 - KAC8) and three isolates were positive for compatibility (KAC3 - KAC10 -KAC11 and KAC4 - KAC8 - KAC10). Three isolates mutually interacted and were selected for further formulation and labeled C 1 (KAC3 - KAC10 - KAC11), C 2 (KAC4 - KAC8 - KAC10), and C 3 (KAC11 - KAC12) consortia . Shelf Life of Individual Actinomycete Isolates in Combined Carrier Materials In our study, the survival of seven different Actinomycete isolates (KAC3, KAC4, KAC6, KAC8, KAC10, KAC11, and KAC12) in a combined carrier material over six months at 28±2°C and 35±2°C, was measured in colony-forming units per gram (CFU/g). In observation of viability at 28±2°C at the start (Month 0), all isolates exhibited relatively high CFU counts, ranging from 10.07 to 10.23 log CFU/g. However, over time, a gradual decline in CFU counts was observed across all isolates. KAC3 maintained the highest CFU count throughout the six-month period, starting at 10.17 log CFU/g and declining to 8.53 log CFU/g by Month 6, showing a more gradual reduction compared to other isolates. Meanwhile, KAC10 showed a moderate decline from 10.10 log CFU/g at the start to 8.04 log CFU/g by the end of the observation period. KAC11 displayed a similar pattern, decreasing from 10.20 to 8.01 log CFU/g. When comparing these isolates, KAC3, KAC10, and KAC11 showed the highest resilience, whereas KAC4, KAC6, KAC8, and KAC12, which experienced moderate levels of viability, are shown in . Upon observation of viability at 35±2°C, at Month 0, all isolates had high CFU counts, ranging from 9.83 to 10.13 log CFU/g. KAC3, starting at 10 log CFU/g, showed a relatively moderate decline to 7.83 log CFU/g by Month 6. KAC10, which started at 10.13 log CFU/g, showed a reduction to 7.64 log CFU/g by Month 6. The KAC11 cells followed a similar trajectory, starting at 10 log CFU/g and decreasing to 7.53 log CFU/g. All isolates experienced a decline in CFU counts over time, with KAC6 showing the most dramatic decrease in viability, and KAC3, KAC10, and KAC11 demonstrating better survival at the higher temperature of 35±2°C. KAC8 and KAC12 showed moderate decline, with KAC4 experiencing a relatively steep decrease. The data suggest that temperature plays a significant role in the survival of these isolates, with faster viability loss observed at 35±2°C compared to lower temperatures, as shown in . Shelf Life of Consortia Actinomycete Isolates in Combined Carrier Materials during Storage Period The populations of the Actinomycete consortia (consortia 1, 2, and 3) in the combined bioformulation stored at two different temperatures (28±2°C and 35±2°C) for up to six months, measured in colony-forming units per gram (CFU/g), are shown in . At 28±2°C, C 1 initially had the highest CFU count (10.27 log CFU/g), which decreased steadily over the six-month period to 8.48 log CFU/g. This consortium demonstrated relatively better stability than the others at this temperature. C 2 started at 10.03 log CFU/g and saw a significant decline to 7.22 log CFU/g by Month 6, indicating the sharpest drop in population among the three consortia. C 3 , beginning at 10.13 log CFU/g, declined to 7.78 log CFU/g by the end of the six months, showing a moderate loss in viability. At 35±2°C, all consortia showed a pronounced reduction in the CFU counts. C 1 , starting at 10.07 log CFU/g, had a slower decline compared to the other two consortia, finishing at 7.65 log CFU/g by month 6. C 2 , which began at 9.83 log CFU/g, exhibited the sharpest drop in population, declining to 6.47 log CFU/g after six months, indicating significant temperature sensitivity. C 3 followed a similar pattern with an initial count of 10.1 log CFU/g, decreasing to 7.02 log CFU/g by month 6. IoT-Based Monitoring of External Parameters for Stored Bioinoculant-Assessed Carrier Materials Four widgets from the Blynk program were employed in this study: a gauge for moisture and humidity content, labeled value for temperature, display value for pH level, and notification system for the color sensor. Software testing was conducted concurrently with testing of each sensor connected to the Blynk application. Monitoring the external parameters using the sensor-applied IoT system predicts the accuracy of the temperature increase from the 1 st month to the end of the 6 th month (27 to 31°C), with a gradual increase in the CO 2 level (491.48 − 1,606.33 ppm), moisture level reduction (60 to 49.67%), and humidity (71 to 65.49%). The external parameters were monitored through IoT using Blynk application under in vitro conditions, as shown in . 

presents the characteristics of the different carrier materials and reveals the notable differences in their properties. In that analysis of pH, electrical conductivity (EC), available Nitrogen, Phosphorus and Potassium (NPK) ratio, total carbon content, and carbon-to-nitrogen (C:N) ratios were demonstrated for agricultural applications. Wood ash has high carbon content, a balanced carbon-to-nitrogen ratio, a reasonable amount of nitrogen, phosphorus, and potassium, and is strongly alkaline and salinized. Charcoal has very high salinity and a somewhat acidic pH. It also has very high phosphorus content and low quantities of potassium and nitrogen. Its high carbon-to-nitrogen ratio suggests that it contains a significant amount of carbon compared with nitrogen. Because it is neutral, eggshell powder has low salinity and a high nutrient content. The vermi-cost method has a moderate salinity level, an almost neutral pH, and a relatively low carbon-to-nitrogen ratio. It also offers a fair amount of nitrogen in relation to its potassium and phosphorus content. The surfactants SDS and CTAB, both mildly acidic, lack nutrients, and are used as adhesives. According to the methodology, the solid-based carrier bioformulation process for a unique formulation is very high in the alkaline range but can be adjusted to neutral (pH 6.5 – 7) conditions using lime (CaO). 

Actinomycete Isolates Seven isolates were further screened for PGPR traits ( represents the in vitro assessment of PGP traits), including IAA, siderophore, phosphate, and potassium solubilization. Among them, seven isolates (KAC3, KAC10, KAC11, and KAC12) were positive for IAA, siderophore, phosphate, and potassium solubilization. Among the seven isolates, KAC3, KAC10, and KAC11 showed extensive zone formation for siderophore, phosphate, and potassium solubilization. Among the seven isolates, KAC3 and KAC11 produced IAA with dark-pink color changes in fully grown cultures under laboratory conditions. Isolate KAC12 showed a moderately positive response for the PGP traits. Among the seven isolates screened, three isolates, KAC3, KAC10, and KAC11, exhibited positive responses to all the in vitro PGPR characteristics studied . 

Seven Actinomycete species isolated from the soil environment in the Virudhunagar District, Tamil Nadu, were collected. The seven Actinomycete isolates were then used for compatibility assays under laboratory conditions: KAC3 (PP550146), KAC4 (PP177363), KAC6 (PP177364), KAC8 (PP177365), KAC10 (PP177366), KAC11 (PP177374), and KAC12 (PP177389) . The results observed for the two isolates were compatible (KAC8 -KAC11, KAC6 - KAC10 and KAC6 - KAC8) and three isolates were positive for compatibility (KAC3 - KAC10 -KAC11 and KAC4 - KAC8 - KAC10). Three isolates mutually interacted and were selected for further formulation and labeled C 1 (KAC3 - KAC10 - KAC11), C 2 (KAC4 - KAC8 - KAC10), and C 3 (KAC11 - KAC12) consortia . 

Actinomycete Isolates in Combined Carrier Materials In our study, the survival of seven different Actinomycete isolates (KAC3, KAC4, KAC6, KAC8, KAC10, KAC11, and KAC12) in a combined carrier material over six months at 28±2°C and 35±2°C, was measured in colony-forming units per gram (CFU/g). In observation of viability at 28±2°C at the start (Month 0), all isolates exhibited relatively high CFU counts, ranging from 10.07 to 10.23 log CFU/g. However, over time, a gradual decline in CFU counts was observed across all isolates. KAC3 maintained the highest CFU count throughout the six-month period, starting at 10.17 log CFU/g and declining to 8.53 log CFU/g by Month 6, showing a more gradual reduction compared to other isolates. Meanwhile, KAC10 showed a moderate decline from 10.10 log CFU/g at the start to 8.04 log CFU/g by the end of the observation period. KAC11 displayed a similar pattern, decreasing from 10.20 to 8.01 log CFU/g. When comparing these isolates, KAC3, KAC10, and KAC11 showed the highest resilience, whereas KAC4, KAC6, KAC8, and KAC12, which experienced moderate levels of viability, are shown in . Upon observation of viability at 35±2°C, at Month 0, all isolates had high CFU counts, ranging from 9.83 to 10.13 log CFU/g. KAC3, starting at 10 log CFU/g, showed a relatively moderate decline to 7.83 log CFU/g by Month 6. KAC10, which started at 10.13 log CFU/g, showed a reduction to 7.64 log CFU/g by Month 6. The KAC11 cells followed a similar trajectory, starting at 10 log CFU/g and decreasing to 7.53 log CFU/g. All isolates experienced a decline in CFU counts over time, with KAC6 showing the most dramatic decrease in viability, and KAC3, KAC10, and KAC11 demonstrating better survival at the higher temperature of 35±2°C. KAC8 and KAC12 showed moderate decline, with KAC4 experiencing a relatively steep decrease. The data suggest that temperature plays a significant role in the survival of these isolates, with faster viability loss observed at 35±2°C compared to lower temperatures, as shown in . 

Actinomycete Isolates in Combined Carrier Materials during Storage Period The populations of the Actinomycete consortia (consortia 1, 2, and 3) in the combined bioformulation stored at two different temperatures (28±2°C and 35±2°C) for up to six months, measured in colony-forming units per gram (CFU/g), are shown in . At 28±2°C, C 1 initially had the highest CFU count (10.27 log CFU/g), which decreased steadily over the six-month period to 8.48 log CFU/g. This consortium demonstrated relatively better stability than the others at this temperature. C 2 started at 10.03 log CFU/g and saw a significant decline to 7.22 log CFU/g by Month 6, indicating the sharpest drop in population among the three consortia. C 3 , beginning at 10.13 log CFU/g, declined to 7.78 log CFU/g by the end of the six months, showing a moderate loss in viability. At 35±2°C, all consortia showed a pronounced reduction in the CFU counts. C 1 , starting at 10.07 log CFU/g, had a slower decline compared to the other two consortia, finishing at 7.65 log CFU/g by month 6. C 2 , which began at 9.83 log CFU/g, exhibited the sharpest drop in population, declining to 6.47 log CFU/g after six months, indicating significant temperature sensitivity. C 3 followed a similar pattern with an initial count of 10.1 log CFU/g, decreasing to 7.02 log CFU/g by month 6. 

Four widgets from the Blynk program were employed in this study: a gauge for moisture and humidity content, labeled value for temperature, display value for pH level, and notification system for the color sensor. Software testing was conducted concurrently with testing of each sensor connected to the Blynk application. Monitoring the external parameters using the sensor-applied IoT system predicts the accuracy of the temperature increase from the 1 st month to the end of the 6 th month (27 to 31°C), with a gradual increase in the CO 2 level (491.48 − 1,606.33 ppm), moisture level reduction (60 to 49.67%), and humidity (71 to 65.49%). The external parameters were monitored through IoT using Blynk application under in vitro conditions, as shown in . 

The results of three types of carrier materials used (peat, rice husks, and local kaolin) showed after 28°C storage for eight weeks that the viable rhizobia count was high in peat compared to that of rice husk and kaolin . Investigation of vermin-cast combined with lignite as a carrier substrate for biofertilizers showed viable cell counts exceeding 10×10 6 CFU/g for Azotobacter chroococcum , Bacillus megaterium , and Rhizobium leguminosarum after ten months . Lignite alone showed no viable cells after six months. Charcoal combined with glycerol exhibited significantly higher microbial counts over a three-month storage period, indicating enhanced stability and longevity of bacterial viability . The effects of anionic (SDS) and cationic (CTAB) surfactants on the stability of binary bacterial co-aggregates, as studied by , revealed that both SDS and CTAB promoted bacterial coaggregation at lower concentrations. However, complete deflocculation of the co-aggregates occurred at higher concentrations of 1 mg/ml SDS and 0.3 mg/l CTAB. Despite the SDS-CTAB pretreatment, the sludge maintained its hydrophobic character and displayed significant co-aggregation of bacteria, retaining 96% viability over a three-month period. A group of potent microorganisms based on in vitro compatibility studies was assembled for comparison . Nine strains were categorized under the genera Bacillus , Streptomyces , Azotobacter , and Frauteria . Previous studies  reported comparable findings using Actinomycetes , fungi, and bacteria. Eight substrates of rice grain, sorghum grain, cotton cake, wheat straw, sawdust, sugarcane bagasse, and wheat bran were utilized by  to mass multiply bioagents, such as Trichoderma harzianum and Gliocladium virens . In sorghum grains, these bioagents showed good development after being transferred to other carriers. Previous researchers have observed similar outcomes using various carriers . Another study assessed for plant growth-promoting rhizobacteria (PGPR) traits, such as indole-3-acetic acid (IAA) production, ammonia and hydrogen cyanide (HCN) production, and phosphate solubilization . Furthermore, they were screened for in vitro salt (NaCl) tolerance and Na + uptake patterns, and two stress-tolerant rhizobacteria, Bacillus pumilus and Bacillus subtilis showed all PGPR traits with tolerance to salinity. The majority of PGPR Actinomycetes synthesize IAA, which is responsible for the increased number of adventitious roots that help plants take up a large volume of nutrients and absorb water, whereas increased root exudates in turn benefit the bacteria. The maximum phosphate solubilization activity was detected in Streptomyces sp. WA-1 (72.13 mg/100 ml). Moreover, previous research has reported 83.3, 58.9, and 39 mg/100 ml phosphate solubilization by Streptomyces cavourensis , Streptomyces griseus , and Micromonospora aurantiaca , respectively . The best strains from each genus, Azospirillum lipoferum VAZS-18, Azotobacter chroococcum VZB-6, Bacillus megaterium VBA-2, and Pseudomonas fluorescens VPS-19, were used to create a carrier-based biofertilizer consortium, which was tested for suitability as a healthy inoculation practice for medicinal crops. In addition to producing effective strains of inoculants, maintaining the viability of microbial cells at a satisfactory level for a longer storage period is equally important . The viable cell counts of all carrier materials examined declined over the course of five weeks at room temperature . At approximately 28°C, coriander husk material produced the greatest results with the highest viable cell count. The ideal storage temperature for these PGPRs was 28°C. The number of surviving individuals in various carrier materials was lower at 25°C than at 40°C. For Azospirillum , Azotobacter , Bacillus , and Pseudomonas , PGPR strains were estimated using single inoculant and consortium preparations for Azospirillum , Azotobacter , Bacillus , and Pseudomonas . At 40°C, the PGPR population in the pressmud, vermiculite, and alginate beads created with a single inoculant significantly decreased, averaged at 35°C, and peaked at 25°C . During a 6-month storage period, Aspergillus flavus NRRL 30793 propagules decreased more at 25°C than at 4°C . In line with this, our findings demonstrated that while room temperature was appropriate for brief storage times, Actinomycetes -isolated strains could withstand 35°C during shelf-life studies for individual strains in long-term storage, apart from room temperature. The findings of , who reported that peat, wheat bran, rice husks, vermiculite, clay, and alginate can be utilized as effective carriers, are consistent with our findings. It is important to note that sterilized carriers typically have substantially longer shelf life and can support bigger populations. Additionally, they demonstrated that, in comparison with autoclaving at 121°C, gamma irradiation almost completely preserved the chemical and physical properties of the material, making it the most appropriate method of carrier sterilization . By studying , we will be able to explain the findings of software and hardware design, as well as the outcomes of device performance testing on every sensor that will be presented on the Blynk monitoring application. In addition, the application of each sensor was tested. We will review the features of the widget and its functionality in the Blynk application before testing starts. Blynk application design for biofertilizer storage can be found in . Fakharulrazi and Yakub monitored the composting of food waste using a sensor-based application using a Blynk app for external parameter sensing . 

In conclusion, C 1 showed the best overall survival under both temperature conditions, whereas C 2 displayed the steepest decline. C 3 showed a moderate reduction in the CFU counts. The packed C 1 consortia formulation, using a dynamic NPK-rich carrier material, exhibited exceptional performance in maintaining strain viability at 28±2°C and 35±2°C temperature conditions. The accuracy of biotic and abiotic factors in the C 1 consortia ( Streptomyces rameus KAC3, Streptomyces calvus KAC10, and Streptomyces werraensis KAC11) was assessed through manual strain population counts and physical factor analysis using IoT devices. Over six months, the physical factors inside the packed product, such as temperature, humidity, CO 2 , and moisture, were monitored digitally and recorded against varying external environmental conditions, maintaining 100% viability of the C 1 consortium strains by verifying the viable count for individual strains in different carrier materials. A consortium-based combined-carrier material formulation was studied for a 6-month duration. The C 1 consortium-based formulation was highly efficient and stable at different temperatures, highlighting its potential as an eco-friendly bioinoculant for sustainable agriculture. 

