SOY MOLASSES AS A SUBSTRATE FOR THE PRODUCTION OF POLYHYDROXYALKANOATES (PHA) BY MIXED MICROBIAL CULTURES: Effects of the Applied Organic Load

• Grant number: 23/05911-3
• Support Opportunities: Scholarships in Brazil - Master
• Start date: April 01, 2024
• End date: February 28, 2025
• Field of knowledge: Engineering - Sanitary Engineering - Water Supply and Wastewater Treatment
• Principal Investigator: Guilherme Henrique Duarte de Oliveira
• Grantee: Andressa Gomes Barroso
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 22/10615-1 - Consolidation of the biorefinery concept applied to the biological treatment of wastewater and solid wastes, AP.TEM

Abstract

Bio-based plastics, or bioplastics, are an alternative to conventional plastics. Polyhydroxyalkanoates (PHA) are completely biodegradable polyesters that can be produced from agro-industrial waste. Soybean molasses seems to be a viable by-product for the manufacture of biopolymers because of its rich carbohydrate content, the increasing consumption of soybean products, and its wide availability in Brazil. PHA are internally generated by certain microorganisms capable of obtaining, storing and consuming their own source of energy and carbon, and can be selected under conditions of alternating substrate availability, called feast-famine (F/F). The mixed microbial cultures (MMC), consortia of microorganisms present in wastewater treatment systems, can be easily obtained, with zero or minimal cost, being an incentive for its use as inoculum for PHA production. The biological production of PHA with the application of CMM involves a three-step process: (i) acidogenic fermentation step; (ii) microorganism enrichment and selection step; and (iii) PHA accumulation step. The enrichment and accumulation of the microorganisms of interest depend on the volumetric organic loading rate (OLR) applied. Thus, this work aims to investigate the effects of OLR for a PHA production system by CMM operated under F/F process at bench scale using acidified soy molasses as substrate. The performance of the consortium enrichment and PHA accumulation reactors will be evaluated by means of kinetic and yield parameters and the generated biopolymer will be characterized.