Transglutaminases are commonly used in a number of manufacturing operations, including the food and pharmaceutical industry, owing to their protein cross-linking properties. Transglutaminases derived from animal tissues and lungs, which were the first origins of this enzyme, are being substituted out in preference of microbial sources, which are less expensive and simpler to generate and purify. Following the identification of microbial transglutaminase (MTGase), the enzyme was formulated for industrial purposes using a conventional fermentation process based on the bacterium S. mobaraensis. Many trials have been conducted in this area in order to improve enzyme efficiency for commercial purposes. Several hosts microorganisms such as E. coli, Y. lipolytica, S. lividans, P. pastoris and C. glutamicum gene expression studies were conducted for transglutaminase production. This study reflects on the MTGase application in two broad industries: food and biotechnology. The usage of mTGase is presented for many food classes, highlighting implementation possibilities and obstacles to further enhance end-product efficiency. Few applications in the textile and leather industry, as well as applications in the PEGylation reaction, the development of antibody drug conjugates, and regenerative medicine, are also addressed.

Transglutaminase (TG) induces protein cross-linking by catalyzing the reaction of acyl transfer. Mature sequence of TG is inactive when express without its pro-region. Since pro-region is critical for inhibiting the TG's action and for correctly folding it extracellularly, the production is either poor or forming inclusion bodies without its pro-region. One of the fundamental steps for higher yield to date is to increase the transcriptional level of the recombinant gene by generating multicopies that could only be accomplished by cloning the concatemers. Here, co-expressing strain was successfully generated by incorporating pro-region into ribosomal DNA (rDNA) sites to achieve different copies. The maximum enzyme activity was up to 3.9u/ml compared to the wild type that was only 2.1u/ml in shake flasks being inducted for 96hrs.This research work provides an important strategy for its pro-region to take advantage of the degree of transglutaminase folding.

There is a growing interest in the pharmaceutical and agrochemicals industries for the use of enantiomerically-pure amino acids. α-keto acids are commonly used in feeds, food additives, pharmaceuticals, and chemical manufacturing. Commonly, most α-keto acids are manufactured by chemical synthesis, but due to the increasing concern for environment-friendly approaches, microbial fermentation and enzymatic transformation are alternative processes for the production of keto acids. Regarding this, L-amino acid deaminase (LAAD), is a major enzyme for α-keto acids production and is only found in Proteus bacteria. In this review, we discussed the recent biological applications of the enzyme LAAD in the production of keto acids, and summarized the recent advancements in the biological production of six important a-keto acids; specifically, phenylpyruvate, α-ketoglutaric acid, pyruvate, αketoisocaproate, α-keto-γ-methylthiobutyric acid, and α-ketoisovaleric acid.

High fructose syrup is an excellent and safe sweetener that can replace sucrose and is widely used in beverages and food products, including soft drinks, ketchup, yogurt, ice cream, chocolate milk, candies, jams, condiments, canned and packaged foods, etc. Besides, after acid dehydration, it can be used as a renewable resource to synthesize bio-petrochemicals. The advantages of high fructose syrup include high sweetness, high solubility, low viscosity, enhanced flavor, good moisture retention, no side effects in acidic foods, and no crystal formation. Due to its potential application, little has been done to satisfy the current market. It can be produced by two main approaches, (i)Chemical method of synthesis accounted several challenges and these include low yield, unacceptable products, expensive, environmentally unfriendly. This review aimed to discuss the engineering B. subtilis 168 which a food-grade microbial cell factory to solve all the challenges from chemical production processes with an improved yield, cost-effective, environmentally friendly, and quality products.GI which isomerizes a reversible reaction of D-glucose into D-fructose requires special conditions for the highlevel yield of HFS biosynthesis such acid pH environment and high temperature which are harsh for wild-type enzymes. Therefore, there is a need to engineer a GRAS B. subtilis 168 for sustainable industrial production. Codon optimization and plasmid engineering have been highlighted.