Microbial amylase

Apphed biocatalysis has its roots in ancient China and Japan in the manufacture of food and alcohohc drinks. Without knowing, man utilized microbial amylases and proteases, in particrrlar for the production of soy-derived foods. In Etrrope too, applied biocatalysis has a long history. Cheese making has always involved the use of enzymes. As far back as about 400 BC, Homer s Iliad mentions the use of kid stomach for making cheese. It was discovered that milk, which was stored in a bag made of a stomach of a recently slaughtered calf, lamb or kid was converted into a semi-sohd substance. Upon pressing of this substance a drier material was obtained (namely cheese) which... 

Fogarty WM (1983) Microbial amylases. In Fogarty WM (ed) Microbial Enzymes and Biotechnology. Applied Science Publishers, London, p 1... 

Dextrose yield, however, can be increased by conducting saccharification at a lower soHds level where the reverse reaction is minimized. Eor instance, dextrose yields of 98.8, 98.2, 97.5, and 96.9% dry basis can be achieved at soHds levels of 10, 15, 20, and 25%, respectively (10). Low soHds operation, however, is not used commercially owing to problems associated with microbial contamination and cost of water removal. Dextrose level can be increased by 0.5—1.5% at normal reaction soHds by using an enzyme such as puUulanase (11) or a B. megaterium amylase (12) in conjunction with... 

Malted barley contains a- and P-amylases along with proteases and phytases. Most standardi2ed microbial en2yme preparations for industrial starch conversion contain approximately 100 times more amylase activity than malt. In beermaking, malt is not just valuable for its en2ymes but also for flavor compounds. 

Enzymatic desizing is one of the oldest nonfood appHcations of commercial amylases. Another type of enzyme, microbial ceUulases, has developed within the textile iadustry as a tool for fabric finishing, ia particular for denim garment finishing. CeUulases can achieve the fashionable worn look traditionaUy obtained by the abrasive action of pumice stones, ie, stone-washing. 

The greatest variety of industrial enzymes are presently derived from microbial sources, with a lesser diversity coming from plant and animal sources 34), Enzymes derived from plant sources and which are used extensively in the food industry include papain, bromelain, ficin, and amylases. Animal enzymes of economic importance include trypsins, lipases, and gastric proteases. 

For the reasons stated above, deep intrusion of degrading microbes into polysaccharide-plastic films is demonstrably and theoretically improbable. Since starch removal does occur when the films are buried in soil, the primary mechanism must be microbial production of amylase in or near a pore, diffusion of the enzyme into pores and diffusion of soluble digestion products back to the surface where they are metabolized (Figure 3). This mechanism would be the only choice when the pore diameter is too small to admit a microbial cell (i.e., at diameters < 0.5 /im). An alternative mechanism could be diffusion of a water-soluble polysaccharide to the film surface, at which point degradation would occur. None of the materials used in these investigations showed loss of starch even when soaked in water for extended periods with microbial inhibitors present. Therefore, diffusion of amylase to the substrate rather than diffusion of the substrate to the film surface is the more likely mechanism. 

The scheme proposed above requires microbial colonization of the material and excludes degradation by amylases and cellulases that are present in soils (28), but are not newly synthesized or associated with microbial cells. Active polysaccharide hydrolases are found in nearly all soils, but these enzymes are primarily bound to soil organic matter or mineral components attachment is firm enough to severely limit migration of the enzymes from surrounding soil to the film. 

Decay will not occur if the dimensions of the degradable component are so small that neither microbial intrusion nor amylase diffusion into the material can take place. 

As has been described in a recent review of low-molecul2u -welght enzyme inhibitors of microbial origin (65), hypotensive coo unds, ccmipounds useful in the treatment of diabetes or obesity, and con unds useful in the treatment of hypercholestremla have been discovered by the screening for inhibitors of catecholamine-synthesizing enzymes, amylase, or 3-hydroxy-3 metl lglu-taryl coenzyme A reductase respectively. 

Including similar activities, amylase, amyloglucosidase, not precisely differentiated Fermentation with the meaning of microbial activity... 

Applied biocatalysis is older than written history. Ancient records, picturing the manufacture of foods and beverages, testily to the involvement of amylases and proteases from microbial, plant or animal origin, without the knowledge of those using them. These ancient applications can therefore be best described as an art and not as a technology or a scientifically defined method. 

Su, Y. C., Chiu, R. J., Yu, N., Chang, W. R. (1984). The microbial production of amylase inhibitor and its application. I. Isolation and cultivation of Streptomyces nigrifaciens NTU-3314. Proceedings of the National Science Council, Republic of China. Part B, Life sciences, 8(4), 292-301. 

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