Caproic acid production from food waste using indigenous microbiota: Performance and mechanisms

Jialing Tang; Hao Yang; Yunhui Pu; Yisong Hu; Jin Huang; Ni Jin; Xinrui He; Xiaochang C Wang

doi:10.1016/j.biortech.2023.129687

Caproic acid production from food waste using indigenous microbiota: Performance and mechanisms

Bioresour Technol. 2023 Nov:387:129687. doi: 10.1016/j.biortech.2023.129687. Epub 2023 Aug 17.

Authors

Jialing Tang¹, Hao Yang², Yunhui Pu³, Yisong Hu⁴, Jin Huang², Ni Jin², Xinrui He², Xiaochang C Wang⁴

Affiliations

¹ Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China. Electronic address: tangjialing88@126.com.
² Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China.
³ Department of Environmental Engineering, School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China; College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
⁴ Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, China.

PMID: 37595807
DOI: 10.1016/j.biortech.2023.129687

Abstract

Caproic acid (CA) production from food waste (FW) is a promising way for waste recycling, while the fermentation processes need further exploration. In this study, FW acidogenic fermentation under different pH (uncontrolled, 4, 5, 6) using indigenous microbiota was investigated. Result showed that substrate hydrolysis, carbohydrate degradation and acidogenesis increased with the increase of pH. Although various microbial communities were observed in FW, lactic acid bacteria (Lactobacillus and Limosilactobacillus) were enriched at pH lower than 6, resulting in lactic acid accumulation. CA (88.24 mM) was produced at pH 6 accounting for 31.23% of the total product carbon. The enriched lactic acid bacteria were directionally replaced by chain elongators (Caproicibacter, Clostridium_sensu_stricto, unclassified_Ruminococcaceae) at pH 6, and carbohydrates in FW were firstly transformed into lactic acid, then to butyrate and CA through lactate-based chain elongation processes. This work provided a novel CA fermentation pathway and further enriched the FW valorization.

Keywords: Caproic acid; Chain elongation; Food waste; Lactic acid fermentation; Microbial community.

MeSH terms

Food
Lactic Acid
Lactobacillales*
Microbiota*
Refuse Disposal*

Substances

hexanoic acid
Lactic Acid