Approaches for refining heterologous protein production in filamentous fungi

Abstract

Fungi combine the advantages of a microbial system such as a simple fermentability with the capability of secreting proteins that are modified according to a general eukaryotic scheme. Filamentous fungi such as Aspergillus niger efficiently secrete genuine proteins but the secretion of recombinant proteins turned out be a difficult task. Aspergillus niger is an attractive organism because of its high secretion capacity and is frequently used as a model organism. Whereas high production yields can be obtained when homologous proteins are expressed, much lower amounts are obtained with the production of heterologous proteins. To fully exploit the potential of filamentous fungi, understanding of the molecular genetics, their physiology, and the glycosylation metabolism has to be investigated and clarified in more detail. This review summarizes recent developments in heterologous protein production by filamentous fungi and also generalizes the possibilities of improving the protein production by various genetic and bioprocessing approaches, thereby easing recognition of filamentous fungi as a relevant and reliable expression platform.

Increasing recombinant protein production in Escherichia coli through metabolic and genetic engineering

“…Furthermore, the use of heterologous gene products is steadily increasing. For example, in 2004, 35% of all enzymes were heterologous proteins [143], whereas in 2009 this number reached 43%.…”

“…Throughout the years, various E. coli strains with different genotypes have been examined for their potential to [143] produce large amounts of these recombinant proteins. An overview of what strains are typically used in HCDCs is given in Table 3; the genotype characteristics of the strains are listed in Table 4.…”

Fungal β-mannanases: Mannan hydrolysis, heterologous production and biotechnological applications

“…Production levels of enzymes in the range of grams per litre are required for commercial production [65]. Several examples of ␤-mannanase production in excess of 1 g/l through heterologous expression in fungal systems have been reported (see Table 1), both for the expression of fungal genes [66][67][68] and for expression of a bacterial B. subtilis ␤-mannanase in Pichia pastoris [69].…”

Heterologous expression of an endo-β-1,4-glucanase gene from the anaerobic fungus Orpinomyces PC-2 in Trichoderma reesei

“…For the secretion of foreign proteins, fusion strategies are used to facilitate translocation in the secretion pathway and to protect the heterologous protein from degrading (de Faria et al 2002;Paloheimo et al 2003Paloheimo et al , 2007Li et al 2007;Sharma et al 2009). In a previously reported study on expression of glycoside hydrolases from anaerobic fungi in T. reesei, a carrier polypeptide sequence was found to be necessary for the transport of the heterologous xylanase from Orpinomyces PC-2 through the secretory pathway (Li et al 2007).…”