Asparagus stem as a new lignocellulosic biomass feedstock for anaerobic digestion: Increasing hydrolysis rate, methane production and biodegradability by alkaline pretreatment

• Published in: Bioresource technology 2014-07, Vol.164, p.78-85
• Main Authors: Chen, Xiaohua, Gu, Yu, Zhou, Xuefei, Zhang, Yalei
• Format: Article
• Language: English
• Subjects: Alkaline pretreatment; Anaerobic digestion; Anaerobiosis - drug effects; Asparagus; Asparagus Plant - chemistry; Asparagus stem; Biodegradability; Biodegradation, Environmental - drug effects; Biological and medical sciences; Biological Oxygen Demand Analysis; Biological treatment of sewage sludges and wastes; Biomass; Biotechnology; Carbon - analysis; Environment and pollution; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Hydrolysis; Hydrolysis - drug effects; Hydrolysis rate; Industrial applications and implications. Economical aspects; Lignin - metabolism; Lignocellulose; Methane; Methane - biosynthesis; Methane production; Nitrogen - analysis; Plant Stems - chemistry; Plant Stems - drug effects; Pretreatment; Sodium Hydroxide - pharmacology; Volatilization - drug effects
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2014.04.070

•Asparagus stem had a C/N ratio of 20.5 and could be used as the sole feedstock for methane production.•The hydrolysis rate was increased with the increasing NaOH dose.•Alkaline pretreatment significantly increased methane production from asparagus stem.•The highest methane production was 242.3mL/g VS for the 6.0% NaOH dose.•The maximal biodegradability of 55.4% was obtained for 6.0% NaOH pretreated asparagus stem. Recently, anaerobic digestion of lignocellulosic biomass for methane production has attracted considerable attention. However, there is little information regarding methane production from asparagus stem, a typical lignocellulosic biomass, by anaerobic digestion. In this study, alkaline pretreatment of asparagus stem was investigated for its ability to increase hydrolysis rate and methane production and to improve biodegradability (BD). The hydrolysis rate increased with increasing NaOH dose, due to higher removal rates of lignin and hemicelluloses. However, the optimal NaOH dose was 6% (w/w) according to the specific methane production (SMP). Under this condition, the SMP and the technical digestion time of the NaOH-treated asparagus stem were 242.3mL/g VS and 18days, which were 38.4% higher and 51.4% shorter than those of the untreated sample, respectively. The BD was improved from 40.1% to 55.4%. These results indicate that alkaline pretreatment could be an efficient method for increasing methane production from asparagus stem.