Pérez-Rangel M, Valdez-Vazquez I, Martínez-Zavala SA, Casados-Vázquez LE, Bideshi DK, Barboza-Corona JE. Evaluation of inhibitory compounds produced by bacteria isolated from a hydrogen-producing bioreactor during the self-fermentation of wheat straw.
J Appl Microbiol 2022;
133:1989-2001. [PMID:
35808847 DOI:
10.1111/jam.15708]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/29/2022] [Accepted: 07/05/2022] [Indexed: 11/28/2022]
Abstract
AIMS
The objective of this study was to evaluate the inhibitory activity of compounds secreted by bacteria isolated from a hydrogen-producing bioreactor to understand how these microorganisms interact in this community.
METHODS AND RESULTS
In vitro inhibitory assays were performed using samples secreted by bacteria subject to different treatments to determine if their inhibitory effect was due to organic acids, non-proteinaceous compounds, or bacteriocin-like inhibitory substances (BLIS). Bacterial isolated were suppressed 43%, 30%, and 27% by neutralized, precipitated, and non-neutralized cell-free supernatants, respectively. Non-hydrogen producers (Non-H2 P) LAB (Lactobacillus plantarum LB1, L. pentosus LB7, Pediococcus acidilactici LB4) and hydrogen producers (H2 P) LAB (Enterococcus faecium F) were inhibited by the production of organic acids, non-proteinaceous compounds, and BLIS. Meanwhile, the obligate anaerobe H2 P (Clostridium beijerinckii B) inhibited by the production of non-proteinaceous compounds and BLIS. The presence of BLIS was confirmed when proteolytic enzymes affected the inhibitory activity of secreted proteins in values ranging from 20 to 42%. The BLIS produced by L. plantarum LB1, P. acidilactici LB4, L. pentosus LB7, and E. faecium F showed molecular masses of ~ 11 kDa, 25 kDa, 20 kDa, and 11 kDa, respectively.
CONCLUSIONS
It was demonstrated antagonistic interactions between Lactobacillus- Enterococcus, and Pediococcus-Enterococcus species, generated by the secretion of organic acids, non-proteinaceous compounds, and BLIS.
SIGNIFICANCE AND IMPACT OF THE STUDY
We report the interactions between LAB isolated from hydrogen-producing bioreactors. These interactions might impact the dynamics of the microbial population during hydrogen generation. Our work lays a foundation for strategies that allow controlling bacteria that can affect hydrogen production.
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