Screening for polyhydroxyalkanoate (PHA)-producing bacterial strains and comparison of PHA production from various inexpensive carbon sources

A total of 20 different strains were isolated, purified and screened for polyhydroxyalkanoate (PHA) production. PHA-producing strains were screened by Nile blue staining and confirmed by Sudan Black B staining. Strain 1.1 was selected for further analysis due to its high PHA production ability. PHA production was optimized and time profiling was calculated. PHA production on various different cheap carbon sources, i.e., sugar industry waste (fermented mash, molasses, spent wash) and corn oil, was compared. Cell dry weight and PHA content (%) were calculated and compared. The 12.53 g/L is the CDW of bacterial strain when grown in medium containing corn oil. It was found that corn oil at 12.53 g/L medium can serve as a carbon source for bacterial growth, allowing cells to accumulate PHA up to 35.63 %. The PhaC gene was amplified to confirm the genetic basis for the production of PHAs. Moreover, 16S rRNA gene sequence analysis showed that strain 1.1 belongs to Pseudomonas species.