Department of Food Science and Human Nutrition, University of Illinois, 905 S. Goodwin Ave., Urbana, IL 61801, USA.
Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 W. Gregory Dr., Urbana, IL 61801, USA.
Viruses. 2018 May 24;10(6):281. doi: 10.3390/v10060281.
Contamination of fuel-ethanol fermentations continues to be a significant problem for the corn and sugarcane-based ethanol industries. In particular, members of the family are the primary bacteria of concern. Currently, antibiotics and acid washing are two major means of controlling contaminants. However, antibiotic use could lead to increased antibiotic resistance, and the acid wash step stresses the fermenting yeast and has limited effectiveness. Bacteriophage endolysins such as LysA2 are lytic enzymes with the potential to contribute as antimicrobials to the fuel ethanol industries. Our goal was to evaluate the potential of yeast-derived LysA2 as a means of controlling contamination. LysA2 intracellularly produced by showed activity comparable to produced LysA2. Lactic Acid Bacteria (LAB) with the A4α peptidoglycan chemotype (L-Lys-D-Asp crosslinkage) were the most sensitive to LysA2, though a few from that chemotype were insensitive. -expressed LysA2, both secreted and intracellularly produced, successfully improved ethanol productivity and yields in glucose (YPD60) and sucrose-based (sugarcane juice) ethanol fermentations in the presence of a LysA2 susceptible LAB contaminant. LysA2 secreting did not notably improve production in sugarcane juice, but it did control bacterial contamination during fermentation in YPD60. Secretion of LysA2 by the fermenting yeast, or adding it in purified form, are promising alternative tools to control LAB contamination during ethanol fermentation. Endolysins with much broader lytic spectrums than LysA2 could supplement or replace the currently used antibiotics or the acidic wash.
燃料乙醇发酵的污染仍然是玉米和甘蔗基乙醇产业的一个重大问题。特别是 家族的成员是主要关注的细菌。目前，抗生素和酸洗是控制污染物的两种主要手段。然而，抗生素的使用可能导致抗生素耐药性增加，而酸洗步骤会对发酵酵母造成压力，并且效果有限。噬菌体溶菌酶如 LysA2 是具有作为燃料乙醇产业中抗菌剂的潜力的裂解酶。我们的目标是评估酵母衍生的 LysA2 作为控制污染的潜在用途。由 产生的细胞内 LysA2 表现出与由 产生的 LysA2 相当的活性。具有 A4α 肽聚糖化学型（L-赖氨酸-D-天冬氨酸交联）的乳酸菌（LAB）对 LysA2 最敏感，尽管该化学型的一些细菌对 LysA2 不敏感。表达的 LysA2，无论是分泌的还是细胞内产生的，都成功地提高了葡萄糖（YPD60）和基于蔗糖（甘蔗汁）的乙醇发酵中 LysA2 敏感的 LAB 污染物存在时的乙醇生产率和产率。在甘蔗汁中，分泌 LysA2 的 并没有显著提高产量，但它确实控制了 YPD60 中发酵期间的细菌污染。发酵酵母分泌 LysA2 或添加纯化形式的 LysA2 是控制乙醇发酵过程中 LAB 污染的有前途的替代工具。具有比 LysA2 更广泛裂解谱的溶菌酶可以补充或替代目前使用的抗生素或酸洗。
