Enzyme of microbial origin

Hydrolytic rancidity results from the hydrolytic degradation of milk lipids. The hydrolysis is catalyzed by lipases and produces free fatty acids (FFAs), some of which have a low flavor threshold and can cause unpleasant flavors in milk and milk products. These flavors are variously described as rancid, butyric, bitter, unclean, soapy or astringent. The lipases involved are of two types indigenous milk enzyme(s) and enzymes of microbial origin. 

Extensive screening of microbial strains proved to be a powerful tool for development of not only antibiotics but also industrial enzymes. Very early discoveries of several unique enzymes of great industrial usefulness and subsequent discoveries of a variety of unique applied enzymes of microbial origins conferred one of the characteristic features on the current biotechnology in Japan (Table 1). 

Table 1. Examples of useful enzymes of microbial origins discovered since 1950 ...

An environmentally friendly safe method developed for the preparation of 3-carbamoyl cephalosporin derivative such as cefuroxime uses o-transcarbomylase, an enzyme of microbial origin for the conversion of 3-hydroxy function to the desired 3-carbomyl group. This new synthesis replaces the conventional chemical route, which employs hazardous isocyanates such as dichlorophosphenyl isocynate or chlorosulfinyl isocyanate to achieve the same conversion (Scheme 57). ... 

Pectins are also responsible for the consistency of sterilised fruits and vegetables, for the pressabiUty of oilseeds, the filterabiUty of fruit juices and the formation of hazes in fruit juices. Some manufacturing processes, for example in the canning industry, use pectolytic enzymes of microbial origin to increase the yield in the production of fruit juices and to maintain their clarity. Pectolytic preparations have also found use in the oenological industry, sugar industry and other sectors. 

Although soil enzyme activities do not consistently correlate with the numbers of microorganisms in soil, or with soil respiratory activities, the contributions from enzymes of microbial origin are considered to be of great importance, and are enhanced under conditions favouring microbial growth and turnover. 

Low-molecular-weight enzyme inhibitors of microbial origin, H. Umezawa, Annu. Rev. Microbiol., 36 (1982) 75-99. 

The enzymatic activity in soil is mainly of microbial origin, being derived from intracellular, cell-associated or free enzymes. Only enzymatic activity of ecto-enzymes and free enzymes is used for determination of the diversity of enzyme patterns in soil extracts. Enzymes are the direct mediators for biological catabolism of soil organic and mineral components. Thus, these catalysts provide a meaningful assessment of reaction rates for important soil processes. Enzyme activities can be measured as in situ substrate transformation rates or as potential rates if the focus is more qualitative. Enzyme activities are usually determined by a dye reaction followed by a spectrophotometric measurement. 

An enzyme inhibitor of microbial origin with a simple structure, fusaric acid (XXXIV), is a hypotensive agent. This compound has been tested clinically as the free acid (29) and as the calcium salt (30) and is orally effective in man with a low incidence of side-effects. Dopamine-p-hydroxylase inhibitory action of this compound has been demonstrated in man (29). 

Umezawa H. (1972) Enzyme Inhibitors of Microbial Origin. University Park Press, Baltimore. 

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. 

Enzyme Treatment. There are a number of enzymes which hydrolyze the microbial cell wall constituents. Enzymes exhibiting these activities include lysozyme, enzyme from snail extract and lytic enzyme systems of microbial origin composed of proteases,... 

Dimitroff, D. and Prodanski, P. 1973. Use of enzyme preparations of microbial origin in kachkaval cheese manufacture. Production of ewes and cows milk kachkaval cheese using an enzyme preparation from Bacillus mesentericus. Milchwissen-schaft 28, 568-571. 

Goranova, L. and Stefanova-Kondratenko, M. 1975. Effect of Bacillus mesentericus strain 76 clotting enzyme on casein fraction, relative to other enzymes of microbial or animal origin. Lait 55, 58-67. 

Enzymes are frequently used as catalysts to promote specific reactions in free solution. They are typically required in small amounts and are attractive in that they obviate both the need to provide the nutritional support which would be required for micro-organisms to perform the same conversion, and the possible subsequent removal of those microbes. Furthermore, the enzyme need not necessarily be of microbial origin so that a wider choice of operating conditions and characteristics may be available. 

Table 1 Enzyme Inhibitors of Microbial Origin Discovered by Omura and Co-workers...

The enzymes responsible for the detrimental effects of lipolysis are of two main types those indigenous to milk, and those of microbial origin. The major indigenous milk enzyme is lipoprotein lipase. It is active on the fat in natural milk fat globules only after their disruption by physical treatments or if certain blood serum lipoproteins are present. The major microbial lipases are produced by psychrotrophic bacteria. Many of these enzymes are heat stable and are particularly significant in stored products. 

D-Mannanases of microbial origin have been re-ported88,93,98,104-106-130 to be both inductive and constitutive enzymes, usually being secreted extracellularly into the medium in which the... 

Fig. 2.11 Enzyme-catalyzed desymmetrization of meso-epoxides using epoxide hydrolases of microbial origin that were screened for maximum activity. Note that the relative rate (measured as the turnover frequency, TOE) offormingthe (R,R)-stereoisomer is about 250 times higher than for the (S,S) one.

Epoxidation of various olefins by cytochrome P-450 enzymes has been studied using rat liver microsomes [29,30] as well as using enzymes from microbial origin. For example, Ruettinger and Fulco [31] reported the epoxidation of fatty acids such as palmitoleic acid by a cytochrome P-450 from Bacillus megaterium. Their results indicate that both the epoxidation and the hydroxylation processes are catalyzed by the same NADPH-dependent monooxygenase. More recently, other researchers demonstrated that the cytochrome P-450cam from Pseudomonas putida, which is known to hydroxylate camphor at a non-activated carbon atom, is also responsible for stereoselective epoxidation of cis- -methylstyrene [32]. The (lS,2R)-epoxide enantiomer obtained showed an enantiomeric purity (ee) of 78%. This result fits the predictions based on a theoretical approach (Fig. 2). 

There are restrictions on some dairy ingredients. For example, enzymes used to make cheese should be of microbial origin to be acceptable as halal. Rennet from calf must be avoided. The active ingredient in rennet is Chymosin. Chymosin can also be produced in the lab, and this biotech product can be halal. Most calf rennet in the US is not halal. 

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