1*Research Scholar, Department of Microbiology, Hindustan Arts & Science College, Padur, Chennai and Head, Department of Microbiology, Apollo Arts and Science College, Chennai. Email: archumb84@gmail.com
2Head, PG Department of Microbiology, Hindustan Arts & Science College, Padur, Chennai. Email: sriniv86@gmail.com
Background: The increasing addition of petroleum-based plastics have been a significant environmental concern because of their non-biodegradable nature and long persistence in ecosystems. Biodegradable polymers like polyhydroxyalkanoates (PHAs) have emerged as promising substitutes to conventional plastics. In these, polyhydroxybutyrate (PHB) is one of the most widely reviewed microbial biopolymers because of its biodegradability, biocompatibility, and thermoplastic properties. PHB is made by various microbes as an intracellular carbon and energy storage compound under conditions of excess carbon and nutrient limitation. Environmental sources like soil ecosystems harbor diverse microbial communities capable of producing PHB. In particular, paddy soil represents a nutrient-rich ecological niche with high microbial diversity, leading to a potential reservoir for effective PHB-producing bacteria.
Objective: The present paper aimed to isolate and identify PHB-producing bacteria from paddy soil and to optimize cultural settings prompting to PHB production for potential application in the production of sustainable bioplastic.
Methods: Soil samples from paddy fields were collected, serially diluted, and then spread plated on nutrient agar for the purpose of bacterial isolation. The isolates have been assessed for PHB synthesis utilizing Nile Blue A fluorescence staining and Sudan Black B staining. The possible PHB-producing isolates were subjected to morphological and biochemical characterisation employing standard microbiological procedures. Additional optimization studies were carried out to assess the effect of various carbon sources, pH levels, nitrogen sources, and incubation temperatures on PHB synthesis.
Results: Various bacterial isolates have been successfully isolated from paddy soil samples, with particular strains showing positive outcomes for PHB accumulation via staining methods. The morphological and biochemical characterisation demonstrated that the isolates were predominantly Gram-negative rod-shaped bacteria. Optimization experiments revealed that certain carbon sources significantly boosted PHB formation, while nitrogen limitation further promoted polymer buildup. Optimal PHB generation was seen with neutral to slightly alkaline pH and modest incubation temperatures.
Conclusion: The findings indicate that paddy soil provides an exciting source of PHB-producing bacteria. Optimization of nutritional and environmental conditions significantly boosted PHB production, indicating the possible application of these isolates for eco-friendly bioplastic manufacturing and sustainable disposal of waste applications.
Keywords: Polyhydroxybutyrate, Biopolymer, PHB-producing bacteria, Soil isolates, Bioplastic, Characterization
How to cite this article: Archana S, Srinivasan T. Isolation And Optimization Of PHB Producing Bacteria From Paddy Soil For Sustainable Bioplastic Production. Int J Drug Deliv Technol. 2026;16(8s): 777-784; DOI: 10.25258/ijddt.16.8s.87
Source of support: Nil.
Conflict of interest: None