Wimalasena Tithira T, Greetham Darren, Marvin Marcus E, Liti Gianni, Chandelia Yogeshwar, Hart Andrew, Louis Edward J, Phister Trevor G, Tucker Gregory A, Smart Katherine A
Bioenergy & Brewing Science, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough, Leicestershire LE12 6RD, UK.
Microb Cell Fact. 2014 Mar 27;13(1):47. doi: 10.1186/1475-2859-13-47.
During industrial fermentation of lignocellulose residues to produce bioethanol, microorganisms are exposed to a number of factors that influence productivity. These include inhibitory compounds produced by the pre-treatment processes required to release constituent carbohydrates from biomass feed-stocks and during fermentation, exposure of the organisms to stressful conditions. In addition, for lignocellulosic bioethanol production, conversion of both pentose and hexose sugars is a pre-requisite for fermentative organisms for efficient and complete conversion. All these factors are important to maximise industrial efficiency, productivity and profit margins in order to make second-generation bioethanol an economically viable alternative to fossil fuels for future transport needs.
The aim of the current study was to assess Saccharomyces yeasts for their capacity to tolerate osmotic, temperature and ethanol stresses and inhibitors that might typically be released during steam explosion of wheat straw. Phenotypic microarray analysis was used to measure tolerance as a function of growth and metabolic activity. Saccharomyces strains analysed in this study displayed natural variation to each stress condition common in bioethanol fermentations. In addition, many strains displayed tolerance to more than one stress, such as inhibitor tolerance combined with fermentation stresses.
Our results suggest that this study could identify a potential candidate strain or strains for efficient second generation bioethanol production. Knowledge of the Saccharomyces spp. strains grown in these conditions will aid the development of breeding programmes in order to generate more efficient strains for industrial fermentations.
在木质纤维素残渣工业发酵生产生物乙醇的过程中，微生物会受到多种影响生产率的因素。这些因素包括生物质原料中释放组成碳水化合物所需预处理过程产生的抑制性化合物，以及发酵过程中微生物所面临的应激条件。此外，对于木质纤维素生物乙醇生产而言，戊糖和己糖的转化对于发酵生物高效、完全转化是一个先决条件。所有这些因素对于最大化工业效率、生产率和利润率都很重要，以便使第二代生物乙醇成为满足未来交通需求的化石燃料在经济上可行的替代品。
本研究的目的是评估酿酒酵母耐受渗透、温度和乙醇应激以及麦秸蒸汽爆破过程中可能释放的抑制剂的能力。表型微阵列分析用于测量作为生长和代谢活性函数的耐受性。本研究中分析的酿酒酵母菌株对生物乙醇发酵中常见的每种应激条件表现出自然变异。此外，许多菌株对不止一种应激具有耐受性，例如对抑制剂的耐受性与发酵应激相结合。
我们的结果表明，本研究可以识别出用于高效第二代生物乙醇生产的潜在候选菌株。了解在这些条件下生长的酿酒酵母菌株将有助于育种计划的开展，以便培育出更适合工业发酵的高效菌株。
