Combination of natural antimicrobials for contamination control in ethanol production

Njl, Maia; Jaf, Corrêa; Rt, Rigotti; Aa, da Silva Junior; Fb, Luciano

doi:10.1007/s11274-019-2734-6

Cited by 10 publications

(7 citation statements)

References 37 publications

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“…Figure 7 shows that there was no obvious change in the morphology of the S. cerevisiae in the buffer solution, the lysozyme solution or the crystallisation solution (lysozyme solution mixed with sodium chloride solution). Under the fluorescence microscope, there was no obvious fragmentation of the S. cerevisiae observed during 96 h in two kinds of solutions with the lysozyme, indicating that lysozyme did not lead to the lysis of the S. cerevisiae, which was in agreement with the literatures 35 , 36 . Most S. cerevisiae survived with lysozyme in the solution, and maintained its morphology during the crystallisation, shown in SEM images of Fig.…”

Section: Resultssupporting

confidence: 90%

“…Lysozyme can act on the β-1,4 bond between N-acetylmuramic acid and N-acetylglucosamine in the peptide polysaccharide molecule, which destroys the cell wall of bacteria, losing its protective effect on cells, and finally makes bacteria dissolve and die 34 . However, lysozyme has limited impact on the cell wall lysis of the S. cerevisiae, due to the lack of lysozyme sites in its cell wall 35 , 36 .…”

Section: Introductionmentioning

confidence: 99%

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Macromolecular protein crystallisation with biotemplate of live cells

Sun

Yang

Miao

et al. 2022

Sci Rep

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Macromolecular protein crystallisation was one of the potential tools to accelerate the biomanufacturing of biopharmaceuticals. In this work, it was the first time to investigate the roles of biotemplates, Saccharomyces cerevisiae live cells, in the crystallisation processes of lysozyme, with different concentrations from 20 to 2.5 mg/mL lysozyme and different concentrations from 0 to 5.0 × 107 (cfu/mL) Saccharomyces cerevisiae cells, during a period of 96 h. During the crystallisation period, the nucleation possibility in droplets, crystal numbers, and cell growth and cell density were observed and analysed. The results indicated the strong interaction between the lysozyme molecules and the cell wall of the S. cerevisiae, proved by the crystallization of lysozyme with fluorescent labels. The biotemplates demonstrated positive influence or negative influence on the nucleation, i.e. shorter or longer induction time, dependent on the concentrations of the lysozyme and the S. cerevisiae cells, and ratios between them. In the biomanufacturing process, target proteins were various cells were commonly mixed with various cells, and this work provides novel insights of new design and application of live cells as biotemplates for purification of macromolecules.

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Section: Resultssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Macromolecular protein crystallisation with biotemplate of live cells

Sun

Yang

Miao

et al. 2022

Sci Rep

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“…Maia et al . (2019) reported bacterial decreases of 1·58 and 5 log cycles when applying hop extract (5 mg l –1 ) and nisin (30 mg l –1 ), respectively, in fermentation tests with co‐culture of S. cerevisiae and L. fermentum , with no negative effects on S. cerevisiae . Previous studies have demonstrated that co‐cultures of S. cerevisiae and L. fermentum submitted to the acid treatment (sulfuric acid, pH 2·0) in fermentation cycles utilizing sugarcane juice (sterilized or not) showed no effect of the acid treatment on the yeast count but a significant decrease in the L. fermentum count (3–5 log CFU ml –1 cycles).…”

Section: Resultsmentioning

confidence: 99%

Mandarin essential oil as an antimicrobial in ethanolic fermentation: Effects on Limosilactobacillus fermentum and Saccharomyces cerevisiae

Varano¹,

Shirahigue²,

Azevedo

et al. 2022

Letters in Applied Microbiology

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Significance and Impact of the Study: Several novel strategies have been explored so far to replace sulfuric acid for cell treatment in the bioethanol industry. Citrus essential oils are reported to be useful in several applications, although none of the reported works involve the application of these oils for combating bacterial contamination in bioethanol production. The present study demonstrated that mandarin essential oil diluted in water could be as effective as an acid treatment against Limosilactobacillus fermentum, and could even achieve the complete elimination of bacterial cells depending on the concentration. However, when L. fermentum was co-cultured with Saccharomyces cerevisiae, the effect on the former was reduced. Nonetheless, the high antimicrobial efficacy of mandarin essential oil against L. fermentum warrants further research for a complete understanding.

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“…Bioethanol fermentation facilities are inherently prone to bacterial contamination found in raw materials such as corn mash and process water [ 4 , 6 , 28 , 29 ] which is difficult to eradicate from facilities [ 30 , 31 ] even with chemical treatments such as hop acids and chlorine-based oxides [ 9 , 10 ]. LAB species, in particular, L. fermentum , have been found to be one of the primary contaminants that thrive under the conditions typically found in bioethanol fermentation, such as low pH, high glucose concentration, and anaerobic conditions, and can have a negative impact on ethanol-producing yeast, leading to unpredictable acute stuck fermentation [ 32 ].…”

Section: Discussionmentioning

confidence: 99%

Novel endolysin LysMP for control of Limosilactobacillus fermentum contamination in small-scale corn mash fermentation

Patel,

Lu,

Liu

et al. 2023

Biotechnol Biofuels

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Background Traditional bioethanol fermentation industries are not operated under strict sterile conditions and are prone to microbial contamination. Lactic acid bacteria (LAB) are often pervasive in fermentation tanks, competing for nutrients and producing inhibitory acids that have a negative impact on ethanol-producing yeast, resulting in decreased yields and stuck fermentations. Antibiotics are frequently used to combat contamination, but antibiotic stewardship has resulted in a shift to alternative antimicrobials. Results We demonstrate that endolysin LysMP, a bacteriophage-encoded peptidoglycan hydrolase, is an effective method for controlling growth of LAB. The LysMP gene was synthesized based on the prophage sequence in the genome of Limosilactobacillus fermentum KGL7. Analysis of the recombinant enzyme expressed in E. coli and purified by immobilized metal chelate affinity chromatography (IMAC) showed an optimal lysis activity against various LAB species at pH 6, with stability from pH 4 to 8 and from 20 to 40 °C up to 48 h. Moreover, it retains more than 80% of its activity at 10% ethanol (v/v) for up to 48 h. When LysMP was added at 250 µg/mL to yeast corn mash fermentations containing L. fermentum, it reduced bacterial load by at least 4-log fold compared to the untreated controls and prevented stuck fermentation. In comparison, untreated controls with contamination increased from an initial bacterial load of 1.50 × 107 CFU/mL to 2.25 × 109 CFU/mL and 1.89 × 109 CFU/mL after 24 h and 48 h, respectively. Glucose in the treated samples was fully utilized, while untreated controls with contamination had more than 4% (w/v) remaining at 48 h. Furthermore, there was at least a fivefold reduction in lactic acid (0.085 M untreated contamination controls compared to 0.016 M treated), and a fourfold reduction in acetic acid (0.027 M untreated contamination controls vs. 0.007 M treated), when LysMP was used to treat contaminated corn mash fermentations. Most importantly, final ethanol yields increased from 6.3% (w/v) in untreated contamination samples to 9.3% (w/v) in treated contamination samples, an approximate 50% increase to levels comparable to uncontaminated controls 9.3% (w/v). Conclusion LysMP could be a good alternative to replace antibiotics for mitigation of LAB contamination in biofuel refineries.

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Combination of natural antimicrobials for contamination control in ethanol production

Cited by 10 publications

References 37 publications

Macromolecular protein crystallisation with biotemplate of live cells

Macromolecular protein crystallisation with biotemplate of live cells

Mandarin essential oil as an antimicrobial in ethanolic fermentation: Effects on Limosilactobacillus fermentum and Saccharomyces cerevisiae

Novel endolysin LysMP for control of Limosilactobacillus fermentum contamination in small-scale corn mash fermentation

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