pH shaped kinetic characteristics and microbial community of food waste hydrolysis and acidification

• Published in: Biochemical engineering journal Vol. 146; pp. 52 - 59
• Main Authors: Ma, Jingwei, Xie, Shanbiao, Yu, Liang, Zhen, Yubin, Zhao, Quanbao, Frear, Craig, Chen, Shulin, Wang, Zhi-wu, Shi, Zhou
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.06.2019
• Subjects: Anaerobic digestion; Food waste; Hydrolysis; Kinetic model; Microbial community; Hydrolysis; Food waste; pH; Kinetic model; Anaerobic digestion; Microbial community
• ISSN: 1369-703X; 1873-295X
• DOI: 10.1016/j.bej.2019.03.004

•Both acidic and basic pH favor hydrolysis but acidification was favored by low pH.•Bacteria decay rate was high at acidic and basic pH but low at neutral pH.•Lactobacillus and Enterococcus dominate acidic and basic digester, respectively. Hydrolysis and acidification of food waste under a wide range of pH (4–11) was investigated to maximize volatile fatty acids (VFA) accumulation and H2 production via kinetic model and microbial analysis. To the best of our knowledge, the highest amount of VFA accumulation reached to 53.87 g/L at pH 6 was reported. A kinetic model describing the hydrolysis and acidification process was developed to access the key kinetic parameters. A bipolar effect of pH on hydrolysis rate was first revealed by developed model, monotonical decline on acidification rate with increase of pH was also found. However, the decay rate of both bacteria group showed a bipolar form, resulting in kinetic favorable conditions for VFA accumulation at pH 5. Sequencing of V4-V5 region of 16S rRNA at Illumina Miseq plateform revealed an overwhelming predominance of Lactobacillus and Enterococcus in acidic and alkaline digester, respectively. Correspondence analysis indicated Lactobacillus, Paralactobacillus, and Clostridium contributed to VFA accumulation while Clostridium, Weissella, and Sporananaerobacter played an important role in H2 production.