Perna Michelle Dos Santos Cordeiro, Bastos Reinaldo Gaspar, Ceccato-Antonini Sandra Regina
Laboratory of Molecular and Agricultural Microbiology, Dept Tecnologia Agroindustrial e Sócio-Economia Rural, Centro de Ciências Agrárias, Universidade Federal de São Carlos, P.O. Box 153, Araras, São Paulo State 13600-970 Brazil.
3 Biotech. 2018 Feb;8(2):119. doi: 10.1007/s13205-018-1143-0. Epub 2018 Feb 7.
The tolerance of the pentose-fermenting yeast to the inhibitors released after the biomass hydrolysis, such as acetic acid and furfural, was surveyed. We first verified the effects of acetic acid and cell concentrations and initial pH on the growth of a strain in a semi-synthetic medium containing acetic acid as the sole carbon source. Second, the single and combined effects of furfural, acetic acid, and sugars (xylose, arabinose, and glucose) on the sugar uptake, cell growth, and ethanol production were also analysed. Growth inhibition occurred in concentrations higher than 10.5 g l acetic acid and initial pH 3.5. The maximum specific growth rate (µ) was 0.023 h and the saturation constant (ks) was 0.75 g l acetic acid. Initial cell concentration also influenced µ. Acetic acid (initial concentration 5 g l) was co-consumed with sugars even in the presence of 20 mg l furfural without inhibition to the yeast growth. The yeast grew and fermented sugars in a sugar-based medium with acetic acid and furfural in concentrations much higher than those usually found in hemicellulosic hydrolysates.
研究了戊糖发酵酵母对生物质水解后释放的抑制剂（如乙酸和糠醛）的耐受性。我们首先在以乙酸为唯一碳源的半合成培养基中，验证了乙酸浓度、细胞浓度和初始pH对菌株生长的影响。其次，还分析了糠醛、乙酸和糖类（木糖、阿拉伯糖和葡萄糖）对糖吸收、细胞生长和乙醇生产的单一及联合影响。当乙酸浓度高于10.5 g/l且初始pH为3.5时，生长受到抑制。最大比生长速率（µ）为0.023 h，饱和常数（ks）为0.75 g/l乙酸。初始细胞浓度也会影响µ。即使存在20 mg/l糠醛，乙酸（初始浓度5 g/l）也能与糖类共同被消耗，且不会抑制酵母生长。该酵母能够在含有乙酸和糠醛的糖基培养基中生长并发酵糖类，其浓度远高于通常在半纤维素水解产物中发现的浓度。
