Long-term medium chain carboxylic acids production from liquor-making wastewater - Parameters optimization and toxicity mitigation

Oct 16, 2026

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Long-term medium chain carboxylic acids (MCCAs) production from Chinese liquor-making wastewater is addressed using an expanded granular sludge bed (EGSB) chain elongation (CE) approach. The study mitigates toxicity of undissociated MCCAs that restricts stable CE reactor operation. Using real waste biomass, it achieves the currently highest MCCAs production rate of 31.12 g COD/(L·d), a 76.80% yield, and sustained production for 485 days. Performance improvements are linked to granule sludge structure, optimized operating parameters, and a microbiome dominated by CE functional bacteria, supporting scalable renewable bioenergy production.

LanguageEnglish

CategoryResearch & Report

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Pages9

Reading Time23 min

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Abstract

1. Introduction

Chemical Engineering Journal 388 (2020) 124218 Contents lists available at ScienceDirect Chemical Engineering Journal journal [homepage:](homepage: www.elsevier. com/locate/cej)[ www.elsevier. com/locate/cej](homepage: www.elsevier. com/locate/cej) | Long-term medium chain carboxylic acids production from liquor-making wastewater: Parameters optimization and toxicity mitigation
Qinglian Wua,b, Xiaochi Fengc, Wanqian Guoa,⁎, Xian Baoa, Nanqi Rena
a State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China b College of Architecture and Environment, Sichuan University, Chengdu 610207, China
c School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, China | | | | --- | --- | --- | | H I G H L I G H T S
• EGSB was used to produce MCCAs from Chinese liquor-making wastewater.
• The study achieved currently highest MCCAs production rate by using real biowaste.
• Granule sludge alleviated the toxic eﬀect of undissociated MCCAs on CE bacteria.
• Clostridium IV dominated the CE reactor microbiome. A R T I C L E I N F O
Keywords:
Chain elongation
Medium chain carboxylic acids Caproate
Caprylate
Granular sludge | G R A P H I C A L A B S T R A C T
A B S T R A C T
Medium chain carboxylic acids (MCCAs) production from waste biomass by an emerging open culture chain elongation (CE) technology is a sustainable and aﬀordable approach for future production of renewable bioenergy. However, the toxicity of undissociated MCCAs limits MCCAs production and the stable operation of CE reactor. By utilizing expanded granular sludge bed (EGSB) as a CE reactor and Chinese liquor-making wastewater (CLMW) as feedstock, this study obtained currently highest MCCAs production rate (31.12 g COD/(L·d)) from real waste biomass with a MCCAs yield of 76.80%, and achieved a long-term and stable MCCAs production (485 days). The stable MCCAs production could be primarily attributed to the mitigation of toxic eﬀects ofundissociated MCCAs on CE bacteria due to the special structure of granule sludge. In addition, the high cell density and quick mass transfer eﬃciency of EGSB, the optimized operating parameters, and the eﬃciently shaped microbiome dominated by CE functional bacteria also contributed to the high MCCAs production. This work showed a potential for MCCAs production from CLMW and lay a foundation for scaling up MCCAs production by EGSB reactor. | | 1. Introduction Non-renewable fossil fuel dominates today’s energy source (~80%), and is increasingly consumed with the rapid development of economy [1]. Recent authoritative report from BP Statistical Review of World Energy (BP, 2018) showed that global average fossil fuel consumption increased at an average annual rate of 1.7% in the past decade, and reached 2.2% in 2017. Particularly, the total fossil fuel consumption rose by 3.1% in China which became the largest growth market for energy for the 17th consecutive year. The immoderate consumption ⁎ Corresponding author. E-mail addresses: [guowanqian@126.com](guowanqian@126.com), [guowanqian@hit.edu.cn](guowanqian@hit.edu.cn) (W. Guo). [https://doi.org/10.1016/j.cej.2020.124218](https://doi.org/10.1016/j.cej.2020.124218) Received 28 November 2019; Received in revised form 22 January 2020; Accepted 24 January 2020 Available online 27 January 2020 1385-8947/ © 2020 Elsevier B.V. All rights reserved. Q. Wu, et al. Chemical Engineering Journal 388 (2020) 124218 inevitably leads to the exhaustion of these resources in the foreseeable future [2]. Therefore, developing alternative chemicals to diverse fossilfuel-based products is signiﬁcant to decelerate the depletion of fossil fuel and mitigate the adverse impacts of fossil fuel depletion on economy development especially for the developing countries like China. Medium chain carboxylic acids (MCCAs), a valuable chemical produced by a

FAQs

What feedstock and reactor system are used to produce MCCAs long-term?

Chinese liquor-making wastewater is used as feedstock, and an expanded granular sludge bed (EGSB) serves as the CE reactor.

How does the study address toxicity limiting MCCAs production?

Granule sludge is used to alleviate the toxic effects of undissociated MCCAs on CE bacteria, enabling stable operation.

What production performance is reported in the study?

The work reports a highest MCCA production rate of 31.12 g COD/(L·d), a 76.80% yield, and stable production lasting 485 days.

Oct 16, 2026

Uploaded by Elsa