title: A biologically inspired variable-pH strategy for enhancing short-chain fatty acids (SCFAs) 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±5mg/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 50g/L. A variable pH increased the net SCFA yield by 23.6%, 29.0%, and 36.6% for concentrations of 10, 30 and 50g/L. Therefore, a variable pH enhanced SCFA accumulation in maize straw fermentation.
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Meng
authors.affiliation: UK Biochar Centre, School of GeoSciences, University of Edinburgh, Crew Building, King's Buildings, Edinburgh EH9 3JN, UK.
authors.forename: Jan
authors.initials: J
authors.lastname: Mumme
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China.
authors.forename: Heng
authors.initials: H
authors.lastname: Xu
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China. Electronic address: wkj@tsinghua.edu.cn.
authors.forename: Kaijun
authors.initials: K
authors.lastname: Wang
mesh_terms: D005232:Fatty Acids, Volatile / Q000378:metabolism*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D012722:Sewage; D014866:Waste Products / Q000032:analysis*; D003313:Zea mays / Q000378:metabolism*
chemical_list: D005232:Fatty Acids, Volatile; D012722:Sewage; D014866:Waste Products
keywords: Anaerobic digestion; Maize straw; Rumen; SCFAs production; pH