Polyhydroxybutyrate (PHB) Production via Bioconversion Using Bacillus pumilus in Liquid Phase Cultivation of the Biomass of Arthrospira platensis Hydrolysate as a Carbon Source

Abstract

The viable production of biopolymers, such as Polyhydroxybutyrate (PHB), depends on the development of alternatives with lower costs and renewable raw materials. The present work investigated the use of the bacterium Bacillus pumilus for the production of PHB using hydrolysate of the Arthrospira platensis biomass as carbon sources in addition to glucose and glycerol. The A. platensis hydrolysate was produced via enzymatic hydrolysis of the biomass using α-amylase (Liquozyme), amyloglucosidase (AMG) and a cellulase cocktail (Cellic CTec2) to produce monosaccharide. The extraction of the biopolymer was performed using a methodology adapted to utilize 50% sodium hypochlorite and chloroform and recrystallization with petroleum ether. The molecular structure of the produced PHB was confirmed using gel permeation chromatography and hydrogen nuclear magnetic resonance. Qualitative analysis was performed using Sudan Black stain and infrared spectroscopy. Substrate consumption was quantified using high-performance liquid chromatography. The PHB granules produced by the bacterium Bacillus pumilus were identified, and the maximum glucose consumption of the bacteria was 2.5 g L−1 when producing PHB with glucose. We highlight that, the use of A. platensis hydrolysate was promising for PHB production and had a positive effect on glucose consumption for Bacillus pumilus growth.