Resolving bacterial contamination of fuel ethanol fermentations with beneficial bacteria – An alternative to antibiotic treatment

Rich, Joseph O.; Bischoff, Kenneth M.; Leathers, Timothy D.; Anderson, Amber M.; Liu, Siqing; Skory, Christopher D.

doi:10.1016/j.biortech.2017.09.067

Cited by 37 publications

(26 citation statements)

References 15 publications

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“…These findings are in accordance with previous studies showing that competition is the major interaction found in microbial communities 26 and that higher-order interactions are common forces involved in shaping the functionality of microbial communities 7,47 . Our findings also show that contamination control methods should be more precise 47 and should discriminate among different species of bacteria 49 . Our analysis identified a key bacterial contaminant-L. amylovorus-whose presence was positively associated with higher ethanol yields.…”

Section: Discussionsupporting

confidence: 58%

“…Our findings predict that adding these consortia to a fermenter during industrial ethanol fermentations would benefit the yeast population and the overall industrial process performance. We hypothesize that this effect could potentially stem both from competition towards other bacteria 49 , through stimulation of the yeast central carbon metabolism 44 , or both.…”

Section: Discussionmentioning

confidence: 99%

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Complex yeast-bacteria interactions affect the yield of industrial ethanol fermentations

Lino

Bajić

Vila

et al. 2020

Preprint

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Microbial communities affect several natural processes, from nutrient cycling to human health. Nevertheless, the mechanisms of interaction between microorganisms and their influence on community functions are not well understood. Sugarcane ethanol fermentations represent a simple microbial community dominated by S. cerevisiae and co-occurring bacteria with a clearly defined functionality. In this study, we dissected the microbial interactions in sugarcane ethanol fermentation by combinatorically reconstituting every possible combination of species, comprising approximately 80% of the biodiversity in terms of relative abundance. Functional landscape analysis showed that higher-order interactions counterbalance the negative effect of pairwise interactions on ethanol yield. In addition, we found that Lactobacillus amylovorus improves the yeast growth rate and ethanol yield by cross-feeding acetaldehyde, as shown by flux balance analysis and laboratory experiments. Our results suggest that Lactobacillus amylovorus could be considered an industrial probiotic with the potential to improve sugarcane ethanol fermentation yields by more than 10%. These data highlight the biotechnological importance of comprehensively studying microbial communities and could be extended to other microbial systems with relevance to human health and the environment.

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Section: Discussionsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Complex yeast-bacteria interactions affect the yield of industrial ethanol fermentations

Lino

Bajić

Vila

et al. 2020

Preprint

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“…Time course up to 72 hrs was chosen as most fermentation without bacterial contamination has been shown to be completed by 72 hrs [53].…”

Section: Methodsmentioning

confidence: 99%

Recombinant Bacteriophage LysKB317 Endolysin Mitigates Lactobacillus Infection of Corn Mash Fermentations

Bischoff

Rich

et al. 2020

Preprint

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Background Commercial ethanol fermentation facilities traditionally rely on antibiotics for bacterial contamination control. Here we demonstrate an alternative approach to treat contamination using a novel peptidoglycan hydrolase (LysKB317) isolated from a bacteriophage, EcoSau. This endolysin was specially selected against Lactobacillus strains that were isolated as contaminants from a fuel ethanol plant. The LysKB317 gene was recombinantly expressed in Escherichia coli as a 33 kDa purified enzyme. Results In turbidity reduction assays, the recombinant enzyme was subjected to a panel of 32 bacterial strains and was active against 28 bacterial strains representing one species of Acetobacter, eight species of Lactobacillus, one species of Pediococcus, three species of Streptococcus, and one species of Weissella. The activity of LysKB317 was optimal around pH 6, but it has broad activity and stability from pH 4.5 – 7.5 up to at least 48 h. Maximum activity was observed at 50°C up to at least 72 hrs. In addition, LysKB317 was stable in 30% ethanol up to at least 72 hrs. In experimentally infected corn mash fermentations, 1 µM endolysin reduced bacterial load by 3-log fold change, while 0.01 µM reduced bacteria by 2-log fold change. Concentration of fermentation products (ethanol, residual glucose, lactic acid, and acetic acids) for infected cultures treated with ≥ 0.01 µM LysKB317 were similar to uncontaminated controls. Conclusion Exogenously added LysKB317 endolysin is functional in conditions typically found in fuel ethanol fermentations tanks and may be developed as an alternative to antibiotics for contamination control during fuel ethanol fermentations.

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“…In recent years, as increasing numbers of cars are produced and used in the world, the demand for vehicle fuel is expanding annually. Some studies have shown that ethanol can be used as an alternative fuel [32][33][34]. The production of ethanol from plants has been known since ancient times, but its substrate is amyloid polysaccharides.…”

Section: Introductionmentioning

confidence: 99%

Studies of Cellulose and Starch Utilization and the Regulatory Mechanisms of Related Enzymes in Fungi

Wang

et al. 2020

Polymers

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Polysaccharides are biopolymers made up of a large number of monosaccharides joined together by glycosidic bonds. Polysaccharides are widely distributed in nature: Some, such as peptidoglycan and cellulose, are the components that make up the cell walls of bacteria and plants, and some, such as starch and glycogen, are used as carbohydrate storage in plants and animals. Fungi exist in a variety of natural environments and can exploit a wide range of carbon sources. They play a crucial role in the global carbon cycle because of their ability to break down plant biomass, which is composed primarily of cell wall polysaccharides, including cellulose, hemicellulose, and pectin. Fungi produce a variety of enzymes that in combination degrade cell wall polysaccharides into different monosaccharides. Starch, the main component of grain, is also a polysaccharide that can be broken down into monosaccharides by fungi. These monosaccharides can be used for energy or as precursors for the biosynthesis of biomolecules through a series of enzymatic reactions. Industrial fermentation by microbes has been widely used to produce traditional foods, beverages, and biofuels from starch and to a lesser extent plant biomass. This review focuses on the degradation and utilization of plant homopolysaccharides, cellulose and starch; summarizes the activities of the enzymes involved and the regulation of the induction of the enzymes in well-studied filamentous fungi.

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Resolving bacterial contamination of fuel ethanol fermentations with beneficial bacteria – An alternative to antibiotic treatment

Cited by 37 publications

References 15 publications

Complex yeast-bacteria interactions affect the yield of industrial ethanol fermentations

Complex yeast-bacteria interactions affect the yield of industrial ethanol fermentations

Recombinant Bacteriophage LysKB317 Endolysin Mitigates Lactobacillus Infection of Corn Mash Fermentations

Studies of Cellulose and Starch Utilization and the Regulatory Mechanisms of Related Enzymes in Fungi

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