Recombinant expression insulin-like growth factor 1 in Bacillus subtilis using a low-cost heat-purification technology

Essential factors, advanced strategies, challenges, and approaches involved for efficient expression of recombinant proteins in Escherichia coli

Producing recombinant proteins is a major accomplishment of biotechnology in the past century. Heterologous hosts, either eukaryotic or prokaryotic, are used for the production of these proteins. The utilization of microbial host systems continues to dominate as the most efficient and affordable method for biotherapeutics and food industry productions. Hence, it is crucial to analyze the limitations and advantages of microbial hosts to enhance the efficient production of recombinant proteins on a large scale. E. coli is widely used as a host for the production of recombinant proteins. Researchers have identified certain obstacles with this host, and given the growing demand for recombinant protein production, there is an immediate requirement to enhance this host. The following review discusses the elements contributing to the manifestation of recombinant protein. Subsequently, it sheds light on innovative approaches aimed at improving the expression of recombinant protein. Lastly, it delves into the obstacles and optimization methods associated with translation, mentioning both cis-optimization and trans-optimization, producing soluble recombinant protein, and engineering the metal ion transportation. In this context, a comprehensive description of the distinct features will be provided, and this knowledge could potentially enhance the expression of recombinant proteins in E. coli.

Factors involved in heterologous expression of proteins in E. coli host

The production of recombinant proteins is one of the most significant achievements of biotechnology in the last century. These proteins are produced in the eukaryotic or prokaryotic heterologous hosts. By increasing the omics data especially related to different heterologous hosts as well as the presence of new amenable genetic engineering tools, we can artificially engineer heterologous hosts to produce recombinant proteins in sufficient quantities. Numerous recombinant proteins have been produced and applied in various industries, and the global recombinant proteins market size is expected to be cast to reach USD 2.4 billion by 2027. Therefore, identifying the weakness and strengths of heterologous hosts is critical to optimize the large-scale biosynthesis of recombinant proteins. E. coli is one of the popular hosts to produce recombinant proteins. Scientists reported some bottlenecks in this host, and due to the increasing demand for the production of recombinant proteins, there is an urgent need to improve this host. In this review, we first provide general information about the E. coli host and compare it with other hosts. In the next step, we describe the factors involved in the expression of the recombinant proteins in E. coli. Successful expression of recombinant proteins in E. coli requires a complete elucidation of these factors. Here, the characteristics of each factor will be fully described, and this information can help to improve the heterologous expression of recombinant proteins in E. coli.

Pilot-Scale Production of Chito-Oligosaccharides Using an Innovative Recombinant Chitosanase Preparation Approach

For pilot-scale production of chito-oligosaccharides, it must be cost-effective to prepare designable recombinant chitosanase. Herein, an efficient method for preparing recombinant Bacillus chitosanase from Escherichia coli by elimination of undesirable substances as a precipitate is proposed. After an optimized culture with IPTG (Isopropyl β-d-1-thiogalactopyranoside) induction, the harvested cells were resuspended, disrupted by sonication, divided by selective precipitation, and stored using the same solution conditions. Several factors involved in these procedures, including ion types, ionic concentration, pH, and bacterial cell density, were examined. The optimal conditions were inferred to be pH = 4.5, 300 mM sodium dihydrogen phosphate, and cell density below 10¹¹ cells/mL. Finally, recombinant chitosanase was purified to >70% homogeneity with an activity recovery and enzyme yield of 90% and 106 mg/L, respectively. When 10 L of 5% chitosan was hydrolyzed with 2500 units of chitosanase at ambient temperature for 72 h, hydrolyzed products having molar masses of 833 ± 222 g/mol with multiple degrees of polymerization (chito-dimer to tetramer) were obtained. This work provided an economical and eco-friendly preparation of recombinant chitosanase to scale up the hydrolysis of chitosan towards tailored oligosaccharides in the near future.

A eukaryotic expression strategy for producing the novel antimicrobial peptide PRW4

The antimicrobial peptide PMAP-36 is a cationic peptide derived from porcine myeloid. The N-terminally paired lysine of PMAP-36 was substituted with tryptophan, and the C-terminal hydrophobic tail was deleted, thereby obtaining the antimicrobial peptide PRW4. PRW4 is a α-helical antimicrobial peptide with broad-spectrum antimicrobial activity. In this study, PRW4 was fused to the 6× His-Trx, and the fusion protein was successfully expressed in Pichia pastoris GS115 from the vector pPICZαA. The maximal induction of recombinant protein occurred in the presence of 1% methanol after 96 h at pH 6.0. After purification by a Ni-NTA resin column and digestion by enterokinase protease, 15 mg of recombinant PRW4 with a purity of 90% was obtained from 1 L of fermentation culture. The results indicated that recombinant PRW4 had similar antimicrobial activity as synthetic PRW4 against bacteria such as Escherichia coli ATCC 25922, Escherichia coli UB 1005, Salmonella typhimurium C7731, Salmonella typhimurium 7913, Salmonella typhimurium ATCC 14028, Staphylococcus aureus ATCC 29213, Staphylococcus epidermidis ATCC 12228, and Streptococcus faecalis ATCC 29212. We have successfully expressed PRW4 in P. pastoris, and this work provides a reference for the production of modified antimicrobial peptides in P. pastoris.