A biologically inspired variable-pH strategy for enhancing short-chain fatty acids (SCFAs) accumulation in maize straw fermentation. (February 2016)

• Record Type: Journal Article
• Authors: Meng, Yao; Mumme, Jan; Xu, Heng; Wang, Kaijun
• Is Part Of: Bioresource technology. Volume 201(2016)
• Page Start: 329
• Page End: 336
• Publication Date: 2016-02
• Subjects: SCFAs production -- Maize straw -- pH -- Anaerobic digestion -- Rumen; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2015.11.064
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Maize straw was fermented to produce short-chain fatty acids (SCFAs) with rumen microorganisms. Higher inoculum ratio shows higher hydrolysis and acidogenesis rate of maize straw fermentation. Neutral pH is optimal pH for hydrolysis process of maize straw fermentation. pH between 5.8 and 7.8 does not influence acidogenesis process of maize straw fermentation significantly. A variable pH condition promotes acid accumulation in maize straw fermentation. Abstract: This study investigates the feasibility of varying the pH to enhance the accumulation of short-chain fatty acids (SCFAs) in the in vitro fermentation of maize straw. The corresponding hydrolysis rate and the net SCFA yield increased as inoculum ratio (VSinoculum /VSsubstrate ) increased from 0.09 to 0.79. The pH were maintained at 5.3, 5.8, 6.3, 6.8, 7.3, and 7.8, respectively. A neutral pH of approximately 6.8 was optimal for hydrolysis. The net SCFA yield decreased by 34.9% for a pH of less than 5.8, but remained constant at approximately 721 ± 5 mg/gvs for a pH between 5.8 and 7.8. In addition, results were obtained for variable and constant pH levels at initial substrate concentrations of 10, 30 and 50 g/L. A variable pH increased the net SCFA yield by 23.6%, 29.0%, and 36.6% for concentrations of 10, 30 and 50 g/L. Therefore, a variable pH enhanced SCFA accumulation in maize straw fermentation.