Regulating Strategies for Producing Carbohydrate Active Enzymes by Filamentous Fungal Cell Factories

Abstract

Filamentous fungi are important eukaryotic organisms crucial in substrate degradation and carbon cycle on the earth and have been harnessed as cell factories for the production of proteins and other high value-added products in recent decades. As cell factories, filamentous fungi play a crucial role in industrial protein production as both native hosts and heterologous hosts. In this review, the regulation strategies of carbohydrate active enzyme expression at both transcription level and protein level are introduced, and the transcription regulations are highlighted with induction mechanism, signaling pathway, and promoter and transcription factor regulation. Afterward, the regulation strategies in protein level including suitable posttranslational modification, protein secretion enhancement, and protease reduction are also presented. Finally, the challenges and perspectives in this field are discussed. In this way, a comprehensive knowledge regarding carbohydrate active enzyme production regulation at both transcriptional and protein levels is provided with the particular goal of aiding in the practical application of filamentous fungi for industrial protein production.

Establishment of the monomeric yellow-green fluorescent protein mNeonGreen for life cell imaging in mycelial fungi

“…The selection of a suitable promoter is critical for the expression of heterologous fluorescent proteins in filamentous fungi. We have chosen the constitutive A. nidulans gpd promoter successfully applied in a variety of fungal species and additionally the inducible S. macrospora Smxyl promoter, previously reported to be functional in Acremonium chrysogenum (Bloemendal et al 2014 ; Zhang et al 2020 ). Therefore, the expression plasmids presented here are likely useful for the expression of mng in filamentous fungi other than S. macrospora .…”

Glutamine involvement in nitrogen regulation of cellulase production in fungi

“…T. reesei can consume a variety of nitrogen-containing compounds with little change in cellulase production, while nitrogen limitation inhibited cell growth and cellulase biosynthesis [ 17 ]. However, compared to the extensive research on the carbon regulation on cellulase production [ 18 – 25 ], less attention has been paid to nitrogen regulation of cellulase production with the underlying mechanism unknown.…”

Effect of Oligosaccharide Degree of Polymerization on the Induction of Xylan-Degrading Enzymes by Fusarium oxysporum f. sp. Lycopersici

“…This was confirmed in A. niger , whereby a low concentration of d -xylose induced xylanases, whereas a higher one repressed them through CreA [ 48 ]. CreA is a C2H2 finger domain that functions as a transcription repressor of CAZymes in filamentous fungi, such as A. niger and Aspergillus nidulans [ 49 , 50 ]. Cre1 is its ortholog and has similar function in Neurospora crassa and Trichoderma ressei [ 49 , 51 , 52 ].…”

“…CreA is a C2H2 finger domain that functions as a transcription repressor of CAZymes in filamentous fungi, such as A. niger and Aspergillus nidulans [ 49 , 50 ]. Cre1 is its ortholog and has similar function in Neurospora crassa and Trichoderma ressei [ 49 , 51 , 52 ]. Stability and function of CreA depend on the CreB–CreC deubiquitination complex, which contributes to the carbon catabolite repression of CreA [ 49 , 53 , 54 , 55 ].…”

“…Cre1 is its ortholog and has similar function in Neurospora crassa and Trichoderma ressei [49,51,52]. Stability and function of CreA depend on the CreB-CreC deubiquitination complex, which contributes to the carbon catabolite repression of CreA [49,[53][54][55].…”