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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Renewable Product Technology Research » Research » Publications at this Location » Publication #412203
Research Project: Antimicrobials for Biorefining and Agricultural Applications

Location: Renewable Product Technology Research

Title: Chimeric endolysin LysKB317 enhances exolytic activity against corn mash fermentation contaminant Limosilactobacillus fermentum

Author
item Lu, Shao
item PATEL, MAULIK - Orise Fellow
item Liu, Siqing
item Skory, Christopher

Submitted to: ASM Conference
Publication Type: Abstract Only
Publication Acceptance Date: 6/14/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Bioethanol fermentation facilities are often susceptible to microbial contamination due to the lack of stringent sterile operating conditions at various stages. Lactic acid bacteria (LAB) are typically found in fermentation tanks, competing for nutrients, and producing acids that inhibit ethanol-producing yeast. This often leads to reduced productivity, lower yields, and stuck fermentations. There is a growing emphasis on utilizing alternative antimicrobials instead of antibiotics to control contamination. We previously discovered a bacteriophage-encoded peptidoglycan hydrolase, an endolysin named LysKB317, that is effective at targeting and lysing gram-positive LAB. LysKB317 comprises of an N-terminus glycoside hydrolase family-like (GH25) enzymatically active domain (EAD) linked by a C-terminus SH3b-like cell binding domain (CBD). In this study, we investigate various chimeric endolysin designs based on wild-type LysKB317 to enhance target efficiency against Limosilactobacillus fermentum, a known problematic LAB contaminant in fuel ethanol fermentation facilities. We hypothesize that increased tandem repeats of either EAD or CBD may enhance the exolytic activity of the enzyme. Utilizing molecular cloning techniques, bacteria lytic assay, small-scale corn mash fermentation, and biofilm reduction assay, we demonstrated distinct enzyme characteristics exhibited by each of the chimeric endolysin. Several of the chimera had improved activity and were able to efficiently control bacterial contamination in corn mash fermentations and restore ethanol productivity to levels comparable to controls without contamination. In addition, we show, for the first time, that LysKB317 and its chimera can treat biofilms formed by L. fermentum. The utilization of modular domains of two or more EAD or CBD from the same endolysin in tandem repeats holds promise for improving the exolytic activity of existing endolysin.