Exploration Of The Molecular Mechanism In Candida Shehatae Response To The Inhibitors

The typical yeast strains of Candida shehatae and Candida tropicalis were selected as theexperimental materials, aiming to break through the key technology bottleneck of the inhibitorsproblem in ethanol fermentation from Lignocellulose hydrolysate. The transcript profile of thesugar metabolism and ethanol fermentation in yeast was established based on theHigh-throughput transcriptome sequencing technology. By means of comparative analysis andexcavate of the Transcriptome sequencing data, universal genes of primary functional protein andenzyme in yeast metabolism were screened out. On this basis, C. shehatae was selected as theobject to verify the response of the crucial inhibitor formic acid by the RQ-PCR technology. Atlast, experiment was carried out to research and analyze the transcription dynamics andmolecular regulation of the key genes in yeast.The results showed that there was significant difference in the response to formic acid whenC. shehatae was cultured on glucose or xylose for ethanol fermentation, respectively. Throughthe xylose fermentation experiment, the concentration of medial lethal and completely suppresseswere8.0g/L and10.0/L respectively. Via the analysis of High-throughput transcriptomesequencing data of C. shehatae,42functional genes was found associated with the pathway ofglucose metabolism, xylose metabolism and ethanol fermentation. Through the contrastiveanalysis of the C. tropicalis EST library sequencing data,16genes related to the xylose-ethanolfermentation were confirmed which were ubiquitous in the yeast cell. Among them, ALDH andADH were efficiently induced by glucose; PDH、TKL、PYK、PDC、XR、XDH、HAGT wereefficiently induced by xylose.RQ-PCR experiment of all the42genes were carried out in different inhibitorconcentrations, then15genes were confirmed as the critical genes responsed to formic acid.XDH、ACS、RKI、TAL、GND1、TKL、ZWF1、XR、PDH、PDC、ADH、GLK、MDH、PFK and ALDH. The result of the kinetics experiment of the genes showed that, in medial lethalconcentration of formic acid, XR and PDH genes showed continue and stable inhibit influence,the response of XDH, ADH and PDC were declined during the ferment process, the expression ofGPD was ever-increasing, and the response effect of GND1, ZWF1and ALDH were showed assigmoid curve.