Biotechnological Advances and Trends in Engineering Trichoderma reesei towards Cellulase Hyperproducer

Cellulase has the biggest contribution to the high production costs of lignocellulose bioconversion and the substantial decrease of its production cost is the key to the commercialization of lignocellulosic biorefineries. Trichoderma reesei has the most robust cellulase among the candidates, which therefore is widely used for cellulase production in industry. This is not because of the size of its cellulase gene pool but its prodigious cargo of cellulase productivity. Still, T. reesei cellulase falls far short of perfection in real-world applications, especially for the composition. This review summarized the biotechnological advances in engineering T. reesei for enhanced cellulase production. Meanwhile, we proposed innovative ideas of systematically optimizing cellulase composition at the transcriptional level and improving cellulase production at the regulation level. Efficient genome editing is essential to achieving that target. Thus, the developments of the tools of multiple gene manipulations were discussed in detail here. This review provides ideas and/or inspirations to the future researches on T. reesei cellulase.