Production and characterization of polyhydroxybutyrate from Vibrio harveyi MCCB 284 utilizing glycerol as carbon source

Aim Production and characterization of polyhydroxybutyrate (PHB) from moderately halophilic bacterium Vibrio harveyi MCCB 284 isolated from tunicate Phallusia nigra. Methods and Results Twenty five bacterial isolates were obtained from tunicate samples and three among them exhibited an orange fluorescence in Nile red staining indicating the presence of PHB. One of the isolates, MCCB 284, which showed rapid growth and good polymer yield, was identified as V. harveyi. The optimum conditions of the isolate for the PHB production were pH 8.0, sodium chloride concentration 20 g l−1, inoculum size 0.5% (v/v), glycerol 20 g l−1 and 72 h of incubation at 30°C. Cell dry weight of 3.2 g l−1, PHB content of 2.3g l−1 and final PHB yield of 1.2 g l−1 were achieved. The extracted PHB was characterized by FTIR, NMR and DSC-TGA techniques. Conclusion An isolate of Vibrio harveyi that could effectively utilize glycerol for growth and PHB accumulation was obtained from tunicate Phallusia nigra. PHB produced was up to 72% based on cell dry weight. Significance and impact of the study This is the first report of an isolate of Vibrio harveyi which utilizes glycerol as the sole carbon source for PHB production with high biomass yield. This isolate could be of use as candidate species for commercial PHB production using glycerol as the feed stock or as source of genes for recombinant PHB production or for synthetic biology. This article is protected by copyright. All rights reserved.