Italo de Andrade Bianchini
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Luciane Sene
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Mário Antônio Alves da Cunha
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Maria das Graças de Almeida Felipe
Abstract
One of the major bottlenecks of the biotechnological production of xylitol by pentose-fermenting yeasts is the presence of toxic compounds in the hemicellulosic hydrolysates, which inhibit the bioconversion of xylose into xylitol. In this work, short-term adaptation was evaluated as a strategy to minimize the toxicity of the sugarcane bagasse hemicellulosic hydrolysate to Candida guilliermondii FTI 20037. Yeast adaptation improved xylose assimilation as well as xylitol production. The beneficial effects of adaptation were more pronounced in the hydrolysate with higher concentration of toxic compounds, leading to an increase of 62.5% in the xylitol volumetric productivity in comparison to the use of non-adapted cells. In this condition, it was also verified the reduction of glycerol production (about 102%), a by-product formed as consequence of cellular stress, indicating a greater tolerance of adapted cells to the toxicity of hydrolysates. Short-term adaptation proved to be a promising strategy to improve considerably the microbial tolerance and overcome the toxicity of hydrolysates.
Short-term Adaptation Strategy Improved Xylitol Production by Candida guilliermondii on Sugarcane Bagasse Hemicellulosic Hydrolysate
