The increasing generation of agro-industrial waste and the demand for sustainable bioproducts have created a need for efficient microbial processes that convert renewable biomass into value-added products. In this study, a microbial consortium was developed for the integrated production of industrial enzymes, organic acids, and biodegradable polyhydroxyalkanoates (PHAs) using agro-waste substrates. Three bacterial isolates with high enzymatic activity were selected from rhizosphere soil: S3-9A (presumptive Bacillus sp.) for amylase production, and S2-7P and S1-2C (presumptive Bacillus subtilis) for protease and cellulase production, respectively. Optimization studies identified pH 7, 30°C, and 2% substrate concentration as the optimum conditions for enzyme production.
The selected isolates were combined to form a stable microbial consortium capable of efficient agro-waste utilization. Qualitative analysis confirmed the production of citric acid and lactic acid on rice paddy and coconut leaf substrates, while ethanol was not detected under the aerobic fermentation conditions used. The consortium also produced intracellular PHAs under nitrogen-limited conditions, confirmed by Sudan Black B, Nile Blue staining, and solvent extraction.
Finally, the developed microbial consortium demonstrated effective conversion of agro-waste into industrial enzymes, organic acids, and biodegradable polymers. These findings highlight its potential as a sustainable approach for agro-waste valorization and eco-friendly bioproduction, with further molecular characterization and pilot-scale studies recommended for industrial application.
