Screening and Isolation of Polyhydroxyalkanoate Producing Bacteria from Goa Coast

Abstract

Conventional petroleum-based plastics do not degrade and have unusually long life span. They cause serious threat to environment by leaching of hazardous chemicals, animal death by entanglement and ingestion. PHAs from microorganisms are promising alternatives to petroleum derived plastics. They are produced by bacteria to store excess carbon when the nutrients are limited. They are biodegradable and biocompatible and have properties similar to petroleum based plastics paving way to applications ranging from packaging to drug delivery. Although, several PHA producing bacteria have been isolated from terrestrial environment, not many studies have been reported from marine environment. This work focuses on screening, isolation and biochemical characterization of PHA producing bacteria from various marine samples collected from Goa coast, and estimation of PHA content from potent isolates. Bacterial Isolation was done on ZoBell’s marine agar plates. Primary screening was done on modified medium incorporated with 2% Glucose and Nile Red. The presence of PHA was confirmed on secondary screening by Nile Red staining. The PHA production was carried out by shake flask method employing two stage fermentation strategy. PHA content was estimated based on percentage of crotonic acid present per unit cell dry weight and the potent isolates with high PHA productivity were selected and extraction was carried out. Identification of the isolates was done by biochemical characterization.