Isolation, Screening And Production Of Polyhydroxyalkanoate (PHA) From Bacteria Isolated From Natural Habitats And Organic Waste Environments

Abstract

Polyhydroxyalkanoates (PHAs) are intracellular storage biopolymers synthesized by numerous microorganisms as polyesters under nutrient-limited conditions. These biopolymers are of considerable interest as sustainable alternatives to conventional petroleum-based plastics. This study aims to isolate and conduct preliminary screening of bacteria capable of PHA production from diverse environments, including soil, water bodies, and organic waste sites. Environmental samples were serially diluted and cultured on selective nutrient media to obtain pure bacterial colonies. Potential PHA-accumulating bacteria were identified through staining with Nile blue A and Sudan Black B, which revealed fluorescent or dark-stained intracellular granules under microscopy—confirming PHA synthesis potential upon nutrient depletion. Positive isolates from preliminary screenings were further subjected to PHA production studies under standard laboratory conditions. The extent of PHA accumulation was quantified by measuring cell dry weight and calculating PHA yield. Initial results indicated that several of the isolated bacterial strains demonstrated significant PHA accumulation capacity. Further research will aim to optimize growth conditions and maximize PHA production levels for these strains. Identification and characterization of effective PHA-producing bacteria support the development of environmentally friendly alternatives to synthetic plastics.