Secretory expression and purification of Bacillus licheniformis keratinase in insect cells

Molecular strategies to enhance the keratinase gene expression and its potential implications in poultry feed industry

The tons of keratin waste are produced by the poultry and meat industry which is an insoluble and protein-rich material found in hair, feathers, wool, and some epidermal wastes. These waste products could be degraded and recycled to recover protein, which can save our environment. One of the potential strategy to achieve this target is use of microbial biotreatment which is more convenient, cost-effective, and environment-friendly by formulating hydrolysate complexes that could be administered as protein supplements, bioactive peptides, or animal feed ingredients. Keratin degradation shows great promise for long-term protein and amino acid recycling. According to the MEROPS database, known keratinolytic enzymes currently belong to at least 14 different protease families, including S1, S8, S9, S10, S16, M3, M4, M14, M16, M28, M32, M36, M38, and M55. In addition to exogenous attack (proteases from families S9, S10, M14, M28, M38, and M55), the various keratinolytic enzymes also function via endo-attack (proteases from families S1, S8, S16, M4, M16, and M36). Biotechnological methods have shown great promise for enhancing keratinase expression in different strains of microbes and different protein engineering techniques in genetically modified microbes such as bacteria and some fungi to enhance keratinase production and activity. Some microbes produce specific keratinolytic enzymes that can effectively degrade keratin substrates. Keratinases have been successfully used in the leather, textile, and pharmaceutical industries. However, the production and efficiency of existing enzymes need to be optimized before they can be used more widely in other processes, such as the cost-effective pretreatment of chicken waste. These can be improved more effectively by using various biotechnological applications which could serve as the best and novel approach for recycling and degrading biomass. This paper provides practical insights about molecular strategies to enhance keratinase expression to effectively utilize various poultry wastes like feathers and feed ingredients like soybean pulp. Furthermore, it describes the future implications of engineered keratinases for environment friendly utilization of wastes and crop byproducts for their better use in the poultry feed industry.

Advances in recombinant protease production: current state and perspectives

Proteases, enzymes that catalyze the hydrolysis of peptide bonds in proteins, are important in the food industry, biotechnology, and medical fields. With increasing demand for proteases, there is a growing emphasis on enhancing their expression and production through microbial systems. However, proteases' native hosts often fall short in high-level expression and compatibility with downstream applications. As a result, the recombinant production of proteases has become a significant focus, offering a solution to these challenges. This review presents an overview of the current state of protease production in prokaryotic and eukaryotic expression systems, highlighting key findings and trends. In prokaryotic systems, the Bacillus spp. is the predominant host for proteinase expression. Yeasts are commonly used in eukaryotic systems. Recent advancements in protease engineering over the past five years, including rational design and directed evolution, are also highlighted. By exploring the progress in both expression systems and engineering techniques, this review provides a detailed understanding of the current landscape of recombinant protease research and its prospects for future advancements.

Keratinases as Versatile Enzymatic Tools for Sustainable Development

To reduce anthropological pressure on the environment, the implementation of novel technologies in present and future economies is needed for sustainable development. The food industry, with dairy and meat production in particular, has a significant environmental impact. Global poultry production is one of the fastest-growing meat producing sectors and is connected with the generation of burdensome streams of manure, offal and feather waste. In 2020, the EU alone produced around 3.2 million tonnes of poultry feather waste composed primarily of keratin, a protein biopolymer resistant to conventional proteolytic enzymes. If not managed properly, keratin waste can significantly affect ecosystems, contributing to environmental pollution, and pose a serious hazard to human and livestock health. In this article, the application of keratinolytic enzymes and microorganisms for promising novel keratin waste management methods with generation of new value-added products, such as bioactive peptides, vitamins, prion decontamination agents and biomaterials were reviewed.

Design of novel enzyme biocatalysts for industrial bioprocess: Harnessing the power of protein engineering, high throughput screening and synthetic biology

Biocatalysts have wider applications in various industries. Biocatalysts are generating bigger attention among researchers due to their unique catalytic properties like activity, specificity and stability. However the industrial use of many enzymes is hindered by low catalytic efficiency and stability during industrial processes. Properties of enzymes can be altered by protein engineering. Protein engineers are increasingly study the structure-function characteristics, engineering attributes, design of computational tools for enzyme engineering, and functional screening processes to improve the design and applications of enzymes. The potent and innovative techniques of enzyme engineering deliver outstanding opportunities for tailoring industrially important enzymes for the versatile production of biochemicals. An overview of the current trends in enzyme engineering is explored with important representative examples.

The tale of a versatile enzyme: Molecular insights into keratinase for its industrial dissemination

Keratinases are unique among proteolytic enzymes for their ability to degrade recalcitrant insoluble proteins, and they are of critical importance in keratin waste management. Over the past few decades, researchers have focused on discovering keratinase producers, as well as producing and characterizing keratinases. The application potential of keratinases has been investigated in the feed, fertilizer, leathering, detergent, cosmetic, and medical industries. However, the commercial availability of keratinases is still limited due to poor productivity and properties, such as thermostability, storage stability and resistance to organic reagents. Advances in molecular biotechnology have provided powerful tools for enhancing the production and functional properties of keratinase. This critical review systematically summarizes the application potential of keratinase, and in particular certain newly discovered catalytic capabilities. Furthermore, we provide comprehensive insight into mechanistic and molecular aspects of keratinases including analysis of gene sequences and protein structures. In addition, development and current advances in protein engineering of keratinases are summarized and discussed, revealing that the engineering of protein domains such as signal peptides and pro-peptides has become an important strategy to increase production of keratinases. Finally, prospects for further development are also proposed, indicating that advanced protein engineering technologies will lead to improved and additional commercial keratinases for various industrial applications.

In vitro synergistic effects of three enzymes from Bacillus subtilis CH-1 on keratin decomposition

Extracellular protease Vpr (Vpr), gamma-glutamyltranspeptidase (GGT; EC 2.3.2.2) and glyoxal/methylglyoxal reductase (YvgN; EC 1.1.1.21) are extracellular enzymes involved in feather degradation, which were identified by secretome analyses from an efficient feather-degrading strain Bacillus subtilis CH-1. The encoding sequences corresponding to the three secretory enzymes were cloned into vector pET22b for recombinant expression in Escherichia coli strain BL21 (DE3). Afterward, the proteins containing the C-terminal His-tag were purified using a Ni-IDA column. The optimal temperatures and pH values for protease activity of recombinant Vpr, GGT, and YvgN were identified as 45 °C/pH 7.0, 40 °C/pH 8.0, and 50 °C/pH 6.0 respectively when casein is the substrate. Furthermore, the synergistic effects of the three enzymes were studied using feather powder as substrate. Vpr was the core enzyme to hydrolyze keratin, while GGT and YvgN were coenzymes providing reducing activities for keratin decomposition. The keratinolytic activity was enhanced to about 1.4-folds when YvgN and Vpr applied together in comparison to Vpr alone. And the keratinolytic activity almost reached to 1.5-folds when all the three enzymes were combined to use. The study provides a novel perspective of the mechanism of keratin degradation by microorganisms, and thereby may also be of relevance for the design of an industrial process for enzymatic keratin degradation; however, additional experiments must be done to substantiate this conclusion.

Non-negligible factors in studying the ApoM-S1P axis using EA.hy926 cells

BACKGROUND

The apolipoprotein M (ApoM)-sphingosine-1-phosphate (S1P) axis was recently identified, and research into its function has received increasing attention. However, there are some factors which might influence the results of studies into the function of the ApoM-S1P axis using the EA.hy926 cells. This study investigated related factors, including coagulation factor VIII (FVIII), ApoM, S1P receptor subtypes (S1PRs), C-myc-tagged, and His-tagged proteins in EA.hy926 cells, as well as the effects of ApoM overexpression on S1PRs.

METHODS

The expression of FVIII, ApoM, S1PRs, C-myc, and His-tagged proteins in EA.hy926 cells was investigated through cellular immunofluorescence. EA.hy926 cells were infected with lentiviruses carrying (OE group) or lacking (NC group) the ApoM gene sequence. A stable cell line expressing ApoM was obtained, and the expression of ApoM mRNA was detected through single tube duplex fluorescence reverse transcription quantitative polymerase chain reaction (RT-qPCR). S1PRs expression was detected by RT-qPCR and Western blotting.

RESULTS

The results showed that EA.hy926 cells expressed FVIII, ApoM, C-myc-tagged, and His-tagged proteins. Moreover, they highly expressed S1PR1, slightly expressed S1PR3, weakly expressed S1PR2, and did not express S1PR4 and S1PR5. ApoM overexpression significantly increased S1PR1 mRNA and protein expression but did not affect the expression of S1PR3. EA.hy926 cells expressed FVIII, suggesting the cell line possesses endothelial cell characteristics and could be used for in vitro studies of the ApoM-S1P axis.

CONCLUSIONS

EA.hy926 cell line is suitable for investigation of the ApoM-S1P axis in vitro. However, Since EA.hy926 cells expressed endogenous ApoM, C-myc and His tagged proteins, the exogenous recombinant ApoM should not be labeled with C-myc and His tags for distinguishing from endogenous ApoM. In addition, overexpression of ApoM should be considered to significantly increase the expression of S1PR1 when studying the APOM-S1P axis.

Microbial Proteases Applications

The use of chemicals around the globe in different industries has increased tremendously, affecting the health of people. The modern world intends to replace these noxious chemicals with environmental friendly products for the betterment of life on the planet. Establishing enzymatic processes in spite of chemical processes has been a prime objective of scientists. Various enzymes, specifically microbial proteases, are the most essentially used in different corporate sectors, such as textile, detergent, leather, feed, waste, and others. Proteases with respect to physiological and commercial roles hold a pivotal position. As they are performing synthetic and degradative functions, proteases are found ubiquitously, such as in plants, animals, and microbes. Among different producers of proteases, Bacillus sp. are mostly commercially exploited microbes for proteases. Proteases are successfully considered as an alternative to chemicals and an eco-friendly indicator for nature or the surroundings. The evolutionary relationship among acidic, neutral, and alkaline proteases has been analyzed based on their protein sequences, but there remains a lack of information that regulates the diversity in their specificity. Researchers are looking for microbial proteases as they can tolerate harsh conditions, ways to prevent autoproteolytic activity, stability in optimum pH, and substrate specificity. The current review focuses on the comparison among different proteases and the current problems faced during production and application at the industrial level. Deciphering these issues would enable us to promote microbial proteases economically and commercially around the world.