Penicillium oxalicum host strain for enhancing expression of filamentous fungi protein

Abstract

The invention discloses a Penicillium oxalicum host strain for enhancing expression of filamentous fungi protein, which is named Penicillium oxalicum M3QDelta15A and collected to China General Microbiological Culture Collection Center, wherein the collection number is CGMCC No.9092. The invention also discloses application of the strain in producing filamentous fungi protein. The experiment proves that the engineering bacterium disclosed by the invention has low secretion background in the aspect of expressing Penicillium oxalicum exoglucanase CBHI. Compared with the expression of host with Penicillium oxalicum strain Delta15A, the Penicillium oxalicum M3QDelta15A host has high protein expression level. When using cheap starch as the carbon source to produce the protein, the Penicillium oxalicum host strain has the advantages of low production cost and short period, and has favorable industrial development and application prospects.

Description

technical field [0001] The invention relates to an engineering bacterial strain with low extracellular secreted protein background on starch, in particular to a host bacterium for improving protein expression of filamentous fungi—Penicillium oxalicum (Penicillium oxalicum), which belongs to the field of genetic engineering. Background technique [0002] Protein expression system refers to the system composed of host, foreign gene, vector and auxiliary components. Through this system, the purpose of exogenous gene expression in the host can be achieved. The host expressing the protein is the organism expressing the protein, which can be bacteria, yeast, plant cells, animal cells, etc. Due to the different characteristics of various organisms, the types of proteins suitable for expression are also different. The most commonly used expression systems for heterologous expression of filamentous fungal proteins, especially glycoside hydrolases, are prokaryotic protein expression...

AI Technical Summary

Problems solved by technology

The disadvantage is that some protein products are easy to degrade, the expression level is uncontrollable, and excessive glycosylation is common when expressing filamentous fungal proteins

[0004] At present, the main expression host of filamentous fungi is the mutant strain Δxyr of Trichoderma reesei, because of the lack of a major positive regulator of cellulase, cellulase cannot be induced and secreted extracellularly. Thereby, a low protein secretion background is formed when culturing on glucose, which is conducive to heterologous expression to obtain a relatively pure target protein, but Trichoderma reesei grows slowly, and it takes about 7 days to complete sporulation on the PDA medium (Uzbas et al. al.2012.A homologous production system for Trichoderma reesei secreted proteins in a cellulase-free background.ApplMicrobiol Biotechnol 93(4):1601-1608)

Since the study of filamentous fungal proteins requires a suitable expression host, and there are few expression hosts available, the only mutant strain of Trichoderma reesei Δxyr grows slowly, which limits the expression of many target proteins and affects our For the related research and commercial application of some proteins, it is of great theoretical and practical significance to construct an expression host that grows fast, can use cheap substrate starch, and has a low extracellular protein secretion background

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