木質纖維素資源高效生物降解轉化中的關鍵科學問題研究

曲音波 鐘耀華 秦玉琪 嚴興 田朝光

摘 要：以高產木質纖維素降解酶的里氏木霉、草酸青霉，以及絲狀真菌遺傳學研究的模式菌粗糙脈孢菌為研究對象，分別對碳源感應（誘導物形成和轉運）、信號傳遞、基因轉錄水平調控、蛋白分泌、酶系重構這5個調控木質纖維素酶高效降解木質纖維素的主要內容進行了深入研究。研究發現調控絲狀真菌纖維素酶合成分泌的新基因。草酸青霉中3個纖維寡糖轉運蛋白CdtC，CdtD與CdtG，和粗糙脈孢菌中兩個纖維寡糖轉運蛋白CDT-1和CDT-2。通過調控真菌細胞將誘導物運輸入細胞這一重要的生理過程，參與纖維素酶合成的調控。發現關鍵信號蛋白TrRas2通過信號調控纖維素酶基因的表達。發現多個在轉錄水平調控纖維素酶基因和半纖維素酶基因轉錄的調控蛋白，包括AmyR、ClrB、CreA、CER-1、CER2、HCR-1等，它們或單獨作用，或協同作用，共同調控纖維素酶基因轉錄水平的表達。發現了10個關鍵功能蛋白11個轉錄調控蛋白參與了與絲狀真菌纖維素酶高效分泌相關的UPR信號通路，對以上關鍵蛋白功能的研究將是解析絲狀真菌纖維素酶高效分泌的分子機制的基礎。篩選出有效提高木質纖維素水解效率的協同因子：包括草酸青霉多糖單加氧酶（PMO）、木質素降解相關酶漆酶LacA。在元基因組的研究中，發現了多個新的、有潛在協同效應的纖維素酶和半纖維素酶基因，并已經用于里氏木霉游離酶系的重構。

關鍵詞：草酸青霉 里氏木霉 粗糙脈孢菌 糖轉運蛋白 轉錄調控蛋白 分泌 重構

Abstract：Our research objects are Trichoderma reesei， Penicillium oxalicum and. Neurospora crassa. The research is focused on carbon source induction， signal pathway， transcriptional regulation， protein secretion， and enzyme reconstruction. Many important genes which encode proteins regulating the expression of cellulase and hemicellulase genes were observed. Three cellodextrin transporters （CdtC， CdtD， and CdtG） founcd in P. oxalicum and two cellodextrin transporters （CDT1 and CDT2） found in N. crassa were reported playing important roles in cellulase induction in the cellulolytic fungus. The Ras2 in T. reesei regulates expression of cellulase genes through the signal pathway. Many transcription proteins were observed including AmyR， ClrB， CreA， CER-1， CER2， and HCR-1. They are involved in transcriptional regulation of expression of cellulase genes. 10 Key proteins and 11 transcription proteins were reported to be involved in UPR pathway which is relating with the high secretion of cellulolytic fungus. Some synergic proteins including polysaccharide monooxygenases （PMOs） in P. oxalicum and laccase in T. reesei were reported enhancing traditional cellulase activity. Many new cellulase and hemicellulase genes were found in metagenome research and some of them have been used in reconstruction of cellulolytic enzymes.

Key Words：Penicillium oxalicum；Trichoderma reesei；Neurospora crassa；Cellodextrin transporters；Transcription proteins；Secretion； Reconstruction

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