Performance and microbial characterization of two-stage caproate fermentation from fruit and vegetable waste via anaerobic microbial consortia

Jiangnan Yu; Zhenxing Huang; Peng Wu; Mingxing Zhao; Hengfeng Miao; Chunmei Liu; Wenquan Ruan

doi:10.1016/j.biortech.2019.03.124

Performance and microbial characterization of two-stage caproate fermentation from fruit and vegetable waste via anaerobic microbial consortia

Bioresour Technol. 2019 Jul:284:398-405. doi: 10.1016/j.biortech.2019.03.124. Epub 2019 Mar 27.

Authors

Jiangnan Yu¹, Zhenxing Huang², Peng Wu³, Mingxing Zhao¹, Hengfeng Miao⁴, Chunmei Liu¹, Wenquan Ruan⁵

Affiliations

¹ Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China.
² Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou 215011, China.
³ School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China.
⁴ Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Engineering Laboratory for Biomass Energy and Carbon Reduction Technology, Jiangnan University, Wuxi 214122, China.
⁵ Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou 215011, China. Electronic address: wqruanjn@gmail.com.

PMID: 30959377
DOI: 10.1016/j.biortech.2019.03.124

Abstract

The regulation of two-stage caproate fermentation from fruit and vegetable waste (FVW) via anaerobic microbial consortia was investigated in this study. The results showed the highest caproate production achieved 14.9 g/L at the optimal inoculum to substrate ratio (ISR) of 2:1, ethanol to acid ratio (E/A) of 4:1, and pH of 7.5. The caproate yield and selectivity respectively reached 0.62 g/g and 80.8% (as COD). In acidification stage, an appropriate ISR provided a high conversion efficiency and more acetate formation, which was beneficial to caproate biosynthesis. In caproate production stage, chain elongation performance was sensitive to E/A and pH condition. Butyrate became the main by-product at low E/A or acidic conditions, while excessive ethanol or alkaline condition seriously suppressed substrate conversion. The caproate fermentation was dominated by Clostridium kluyveri. Furthermore, caproate formation was uncoupled with Clostridium kluyveri proliferation, which was mainly generated during the middle and late stages of growth.

Keywords: Anaerobic microbial consortia; Chain elongation; Clostridium kluyveri; Fruit and vegetable waste; Two-stage caproate fermentation.

MeSH terms

Anaerobiosis
Butyrates / metabolism
Caproates / metabolism*
Clostridium kluyveri / metabolism
Ethanol / metabolism
Fermentation*
Fruit / metabolism*
Microbial Consortia*
Vegetables / metabolism*

Substances

Butyrates
Caproates
hexanoic acid
Ethanol