The co-utilization of mixed (pentose/hexose) sugars constitutes a challenge for microbial fermentations. The fungus Ashbya gossypii, which is currently exploited for the industrial production of riboflavin, has been presented as an efficient biocatalyst for the production of biolipids using xylose-rich substrates. However, the utilization of xylose in A. gossypii is hindered by hexose sugars. Three A. gossypii homologs (AFL204C, AFL205C and AFL207C) of the yeast HXT genes that code for hexose transporters have been identified and characterized by gene-targeting approaches. Significant differences in the expression profile of the HXT homologs were found in response to different concentrations of sugars. More importantly, an amino acid replacement (N355V) in AFL205Cp, introduced by CRISPR/Cas9-mediated genomic edition, notably enhanced the utilization of xylose in the presence of glucose. Hence, the introduction of the afl205c-N355V allele in engineered strains of A. gossypii will further benefit the utilization of mixed sugars in this fungus.

混合糖（戊糖/己糖）的共同利用构成了微生物发酵的挑战。目前已被用于工业生产核黄素的真菌Ashbya gossypii被证明是使用富含木糖的底物生产生物脂质的有效生物催化剂。然而，木糖利用中的棉蚜由己糖阻碍。三对棉蚜同源物（AFL204C，AFL205C和AFL207C酵母）HXT基因，对于己糖转运代码已被鉴定和表征通过基因靶向方法。HXT表达谱的显着差异发现同系物对不同浓度的糖有反应。更重要的是，CRISPR / Cas9介导的基因组版本引入了AFL205Cp中的氨基酸替代（N355V），可显着提高葡萄糖存在下木糖的利用率。因此，引入的afl205c-N355V中的工程化菌株等位基因棉蚜将进一步受益混合糖的利用在此真菌。