Microbial Ecological Mechanism for Long-Term Production of High Concentrations of n-Caproate via Lactate-Driven Chain Elongation

Copyright © 2021 American Society for Microbiology..

Lactate-driven chain elongation (LCE) has emerged as a new biotechnology to upgrade organic waste streams into a valuable biochemical and fuel precursor, medium-chain carboxylate, n-caproate. Considering that a low cost of downstream extraction is critical for biorefinery technology, a high concentration of n-caproate production is very important to improve the scale-up of the LCE process. We report here that in a nonsterile open environment, the n-caproate concentration was increased from the previous record of 25.7 g·liter-1 to a new high level of 33.7 g·liter-1 (76.8 g chemical oxygen demand [COD]·liter -1), with the highest production rate being 11.5 g·liter-1·day-1 (26.2 g COD·liter -1·day-1). In addition, the LCE process remained stable, with an average concentration of n-caproate production of 20.2 ± 5.62 g·liter-1 (46.1 ± 12.8 g COD·liter -1) for 780 days. Dynamic changes in taxonomic composition integrated with metagenomic data reveal the microbial ecology for long-term production of high concentrations of n-caproate: (i) the core microbiome is related to efficient functional groups, such as Ruminococcaceae (with functional strain CPB6); (ii) the core bacteria can maintain stability for long-term operation; (iii) the microbial network has relatively low microbe-microbe interaction strength; and (iv) low relative abundance and variety of competitors. The network structure could be shaped by hydraulic retention time (HRT) over time, and long-term operation at an HRT of 8 days displayed higher efficacy.IMPORTANCE Our research revealed the microbial network of the LCE reactor microbiome for n-caproate production at high concentrations, which will provide a foundation for designing or engineering the LCE reactor microbiome to recover n-caproate from organic waste streams in the future. In addition, the hypothetical model of the reactor microbiome that we proposed may offer guidance for researchers to find the underlying microbial mechanism when they encounter low-efficiency n-caproate production from the LCE process. We anticipate that our research will rapidly advance LCE biotechnology with the goal of promoting the sustainable development of human society.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:87

Enthalten in:

Applied and environmental microbiology - 87(2021), 11 vom: 11. Mai

Sprache:

Englisch

Beteiligte Personen:

Zhu, Xiaoyu [VerfasserIn]
Feng, Xin [VerfasserIn]
Liang, Cheng [VerfasserIn]
Li, Jiabao [VerfasserIn]
Jia, Jia [VerfasserIn]
Feng, Leiyu [VerfasserIn]
Tao, Yong [VerfasserIn]
Chen, Yinguang [VerfasserIn]

Links:

Volltext

Themen:

1F8SN134MX
33X04XA5AT
Caproates
Hexanoic acid
Journal Article
Lactate-driven chain elongation
Lactic Acid
Microbial ecology
N-caproate
Organic waste streams
Research Support, Non-U.S. Gov't
Valuable biochemical

Anmerkungen:

Date Completed 01.06.2021

Date Revised 12.11.2021

published: Electronic-Print

Citation Status MEDLINE

doi:

10.1128/AEM.03075-20

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM322980615