Influence of carbon dioxide and nitrogen source on sustainable production of succinic acid from Miscanthus hydrolysates

Abstract

—This study presents sustainable succinic acid production from lignocellulosic hydrolysates, using A. succinogenes, which consumes CO2 during succinic fermentation. Optimal combination of carbon source (gaseous and/or solid MgCO3, 15-30 g/dm3) and nitrogen source (mixtures of yeast extract and hydrolyzed rapeseed cakes: 100:0, 80:20, 60:40, 50:50 and 40:60 % w/w) were experimentally determined. Obtained results stated that simultaneous addition of gaseous CO2 and MgCO3 (20-30 g/dm3) resulted in the highest sugar conversion (89-95%) and succinic yields (66-74%). Additionally, CH4 content in biogas, used as CO2 source, was increased by 21-22% and reached 91-92% after succinic fermentation with addition of MgCO3 (20 g/dm3). The course of succinic fermentation confirmed that 50% of nitrogen dosage can be added as rich in amino acids rapeseed cakes, originated from biodiesel production. Succinic fermentation with gaseous CO2 as the only CO2 or after replacing more than 50% of nitrogen dosage as rapeseed cakes, resulted in increased acetic and formic acids production (by-products of succinic fermentation). Optimal conditions of succinic fermentation (CO2 source and dosage, waste nitrogen source) identified in this study can pave the way towards sustainable production of succinic acid from lignocellulosic biomass.