Acidogenic Fermentation of Polyhydroxybutyrate (PHB) Biopolymer for Short-Chain Fatty Acids Production: Effect of Inoculum to Substrate Ratio, PHB Pre-Treatment and Operating Temperature

Bio-based polymers such as polyhydroxybutyrate (PHB) have emerged as an environmentally benign alternative to conventional petroleum-derived plastics due to their high biodegradability. Acidogenic fermentation is an emerging biotechnology that can convert PHB waste to short-chain fatty acids (SCFAs) which is used as a precursor in the PHB manufacturing process, thereby fostering a closed-loop waste management model. This study aimed to expand the applicability of the acidogenic fermentation process for efficient management of PHB waste by investigating the impact of inoculum to substrate ratio (ISR), impact of PHB pretreatment and impact of operating temperature on hydrolysis and SCFA production. The results showed enhanced hydrolysis and SCFA yield from PHB with increase in ISR. Pretreatment of the PHB pellets led to higher hydrolysis and SCFA yield while operation at mesophilic temperature also resulted in increased hydrolysis and SCFA yield from PHB. The dominant SCFAs found in this study were acetate and butyrate.