Screening of PHA-Producing Bacteria Using Biodiesel-Derived Waste Glycerol as a Sole Carbon Source

Abstract

Different sources of wastewater and soil were used to screen for PHA-producing bacteria using biodiesel-derived waste glycerol as a sole carbon source by the Nile red staining method together with polymer determination. Twelve out of twenty-six isolates from biodiesel-contaminated wastewater consortium were screened for their PHA accumulation ability by cultivation in mineral salt medium supplemented with waste glycerol. The AIK7 isolate was chosen as a potential PHA producer. The PHA production on waste glycerol was examined using pure glycerol as a control substrate. The PHA content of AIK7 isolate cultivated in 10 g/L glycerol could reach 35% cell dry weight in 72 hours from waste glycerol and 33% cell dry weight in 120 hours from pure glycerol cultivation. It can be seen that at this content of waste glycerol, AIK7 isolate is effectively capable of biotransforming glycerol into polymer from low-grade glycerol.