Polyhydroxyalkanoates (PHA) production using single or mixture of fatty acids with Bacillus sp. CYR1: Identification of PHA synthesis genes

Abstract

Competence of the bacteria Bacillus sp. CYR1 to utilize the fatty acids for its growth and polyhydroxyalkanoates (PHA) production was evaluated. Bacterial growth pattern and PHA production was monitored periodically. Bacteria showed highest PHA production (33% DCW) with mixture of four fatty acids (acetic:propionic:butyric:caproic acid). In the case of single fatty acids bacteria showed highest PHA production (22% DCW) with acetic acid. Among various fatty acids, bacteria utilized highest portion of acetic acid (68%), valeric acid (62%) and bacteria were unable to utilize higher chain fatty acids. Produced PHA was confirmed as a copolymer of P(3HB-co-3 HV) having higher portion of hydroxy butyrate (HB) content. Also, four genes (phaA, phaB, phaC, phaJ) involved in PHA synthesis was identified using PCR-sequencing method. Based on these studies, we understood that fatty acids persistent in wastewaters might be feed to the strain CYR1 to produce valuable chemicals like PHA.