How to achieve high-level expression of microbial enzymes

Abstract

Microbial enzymes have been used in a large number of fields, such as chemical, agricultural and biopharmaceutical industries. The enzyme production rate and yield are the main factors to consider when choosing the appropriate expression system for the production of recombinant proteins. Recombinant enzymes have been expressed in bacteria (e.g., Escherichia coli, Bacillus and lactic acid bacteria), filamentous fungi (e.g., Aspergillus) and yeasts (e.g., Pichia pastoris). The favorable and very advantageous characteristics of these species have resulted in an increasing number of biotechnological applications. Bacterial hosts (e.g., E. coli) can be used to quickly and easily overexpress recombinant enzymes; however, bacterial systems cannot express very large proteins and proteins that require post-translational modifications. The main bacterial expression hosts, with the exception of lactic acid bacteria and filamentous fungi, can produce several toxins which are not compatible with the expression of recombinant enzymes in food and drugs. However, due to the multiplicity of the physiological impacts arising from high-level expression of genes encoding the enzymes and expression hosts, the goal of overproduction can hardly be achieved, and therefore, the yield of recombinant enzymes is limited. In this review, the recent strategies used for the high-level expression of microbial enzymes in the hosts mentioned above are summarized and the prospects are also discussed. We hope this review will contribute to the development of the enzyme-related research field.

Production of valuable compounds by molds and yeasts

“…Recombinant proteins are also made by other fungi such as Hansenula polymorpha, K. lactis, Schizosaccharomycs pombe, C. boidini, A. oryzae, A. niger, Trichoderma reesei, T. atroviride, Penicillium sordida, Penicillium griseoroseum, Penicillium purpurogenum and R. oryzae. 135 The products of these heterologous enzymes include citric acid, isocitric acid, α-ketoglutaric acid, succinic acid, polyunsaturated fatty acids such as γ-linoleic acid, EPA and carotenoids including lycopene and β-carotene.…”

Use of a Sec signal peptide library from Bacillus subtilis for the optimization of cutinase secretion in Corynebacterium glutamicum

“…These mostly monoderm bacteria are robust in terms of cultivation conditions, low nutritional demand, and are able to secrete proteins into the extracellular medium [3, 4]. Next to Bacillus  sp., a powerful expression host for the production of technical enzymes [5], Corynebacterium glutamicum is an attractive alternative host microorganism with demonstrated protein secretion capacity in the g/L-range [6, 7].…”

Microbial metabolites in nutrition, healthcare and agriculture

“…of industrial and domestic wastes (Li et al 2012; Choi et al 2015). The biotechnological developments have led to the manipulation of the microorganisms through recombinant DNA technology, protein engineering and their production in appropriate quantities to meet the demand (Liu et al 2013). According to a market analysis, the global market of industrial enzymes was estimated $4.2 billion in 2014 and is predicted to grow at compound annual growth rate (CAGR) of 7% from 2015 to 2020 (Industrial Enzymes Market 2015).…”