Department of Medicine (Infectious Disease Division), School of Medicine & Public Health, University of Wisconsin-Madison, Madison, WI, USA.
Department of Medical Microbiology, School of Medicine & Public Health, University of Wisconsin-Madison, Madison, WI, USA.
Appl Microbiol Biotechnol. 2021 Mar;105(6):2411-2426. doi: 10.1007/s00253-021-11132-1. Epub 2021 Feb 25.
Yeast whole cells have been widely used in modern biotechnology as biocatalysts to generate numerous compounds of industrial, chemical, and pharmaceutical importance. Since many of the biocatalysis-utilizing manufactures have become more concerned about environmental issues, seawater is now considered a sustainable alternative to freshwater for biocatalytic processes. This approach plausibly commenced new research initiatives into exploration of salt-tolerant yeast strains. Recently, there has also been a growing interest in possible applications of microbial biofilms in the field of biocatalysis. In these complex communities, cells demonstrate higher resistance to adverse environmental conditions due to their embedment in an extracellular matrix, in which physical, chemical, and physiological gradients exist. Considering these two topics, seawater and biofilms, in this work, we characterized biofilm formation in seawater-based growth media by several salt-tolerant yeast strains with previously demonstrated biocatalytic capacities. The tested strains formed both air-liquid-like biofilms and biofilms on silicone surfaces, with Debaryomyces fabryi, Schwanniomyces etchellsii, Schwanniomyces polymorphus, and Kluyveromyces marxianus showing the highest biofilm formation. The extracted biofilm extracellular matrices mostly consisted of carbohydrates and proteins. The latter group was primarily represented by enzymes involved in metabolic processes, particularly the biosynthetic ones, and in the response to stimuli. Specific features were also found in the carbohydrate composition of the extracellular matrix, which were dependent both on the yeast isolate and the nature of formed biofilms. Overall, our findings presented herein provide a unique data resource for further development and optimization of biocatalytic processes and applications employing seawater and halotolerant yeast biofilms.Key points• Ability for biofilm formation of some yeast-halotolerant strains in seawater medium• ECM composition dependent on strain and biofilm-forming surface• Metabolic enzymes in the ECM with potential applications for biocatalysis.
酵母细胞已被广泛应用于现代生物技术中，作为生物催化剂来生成许多具有工业、化学和制药重要性的化合物。由于许多利用生物催化的制造企业越来越关注环境问题，因此海水现在被认为是生物催化过程中替代淡水的可持续选择。这种方法很可能引发了对耐盐酵母菌株的新研究计划。最近，微生物生物膜在生物催化领域的潜在应用也引起了越来越多的关注。在这些复杂的群落中，由于细胞嵌入在存在物理、化学和生理梯度的细胞外基质中，因此对不利环境条件表现出更高的抵抗力。考虑到这两个主题，海水和生物膜，在这项工作中，我们通过具有先前证明的生物催化能力的几种耐盐酵母菌株来表征海水基生长培养基中的生物膜形成。测试的菌株在空气-液体样生物膜和硅树脂表面上形成生物膜，Debaryomyces fabryi、Schwanniomyces etchellsii、Schwanniomyces polymorphus 和 Kluyveromyces marxianus 表现出最高的生物膜形成能力。提取的生物膜细胞外基质主要由碳水化合物和蛋白质组成。后者主要由参与代谢过程的酶组成，特别是生物合成酶，以及对刺激的反应。在细胞外基质的碳水化合物组成中也发现了一些特定的特征，这些特征既取决于酵母分离株，也取决于形成的生物膜的性质。总的来说，我们在此提出的研究结果为进一步开发和优化利用海水和耐盐酵母生物膜的生物催化过程和应用提供了独特的数据资源。
