Trends and Challenges in Enzymatic Bioengineering of Natural Products to Industrially Valuable Products: Status and Future of Industrial Enzymology

Background

Studies on production of various industrially valuable products from cheap natural substrates using enzymes and their uses have been summarised in Table 1. Generation of bioactive peptides through enzymatic routes and strategies from food processing industry have already been studied in detail (Toldra, Reig, Aristoy, & Mora, 2017). Enzymatic or biological conversion of renewable lignocellulosic biomass to biofuel or other high-value product are considered to be having high potential. as lignin can be converted to different polymersusing laccase or laccase mediated system. Similarly, fat waste from cooking oil can be interesting substrates for production of biodiesel using microbial lipase. Fishery wastes or dairy wastes rich in protein with the help of protease enzyme can be used for generation of bioactive peptides. Phenolic antioxidants can also be generated using microbial enzymes from different wastes. A number of bioactive compounds like anti-oxidants (flavonols, flavonons, phenolic acids, Anthocyanidines, anthocyanins, carotenoids etc), antibacterial saponins, pectins, amino acid and proteins, lignin and xyloglucans, dietary fibers, glycosides and bioactive lipids have been reportedly present in fruit processing wastes (Banerjee, Singh, Vijayraghvan, MacFarlane, Ptti, & Arora, 2017). Although all these processes involve microbial enzymes these are not considered feasible at industrial scale in their native form. Enzyme engineering focusses on overexpression of enzyme proteins as well as other approaches for improvement in their specificity and stability to enhance the productyield. Very few immobilized enzymes have been used at commercial scale (DiCosimo, McAuliffe, Poulose, & Bohlmann, 2013) and advantageous forcontinuous production, enhanced stability and downstream processing. Glucose isomerase immobilization for production of high fructose corn syrup (HFCS)and also enhanced production of glucose from cellulosic biomass for ethanol productionhave been done. Non-digestible fructooligosaccharides as prebiotics and hydroxymethyl furfural synthesis have also been possible using glucose isomerase enzyme in immobilized form.