Carotenoids microbial production

Several pigments, vitamins and coenzymes like carotenoids, riboflavin (B2), cobal-amine (B12), ascorbic acid (Q, ergosterol (D2), biotin (H), gibberellin, etc. are produced during the normal metabolism of microorganisms. Microbial production of some of... 

Use of Microorganisms for the Bioconversion of Primary Carotenoid Degradation Products. Microbial systems are frequently used for biotransformation... 

Despite the availability of a variety of natural and synthetic carotenoids, there is currently renewed interest in microbial sources. Microorganisms accumulate several types of carotenoids as a part of their response to various environmental stresses. Microbial production of carotenoids, when compared with extraction from vegetables or chemical synthesis, seems to be of paramount interest mainly because of the problems of seasonal and geographic variability in the production and marketing of several of the colorants of plant origin. 

Microbial production of carotenoids is an environmentally friendly method compared to chemical methods. The availability of carotenoid genes from carotenogenic microbes has made possible the synthesis of carotenoids in non-carotenogenic microbes [80]. E. coli, because of its ease for genetic manipulation, is considered a suitable host for carotenoid production and is able to make various carotenoids such as lycopene, P-carotene, canthaxanthin, zeaxanthin, and astaxanthin [81-83]. 

Abscisic aoid is primarily a plant growth inhibitor. Besides its involvement in abscission, it is involved in other physiological actions such as the dormancy of seeds and ion uptake by roots. It is formed biosynthetically from mevalonate, and whereas it could arise by fragmentation of carotenoids-, the intermediates have not been established. It lias not yet been reported as a microbial product, but this probably merely reflects that it has not been looked for. Mucoraceous fungi, which are common in soils, can... 

Genomic and molecular tools have made great impacts on plant biotechnology and offer potential for manipulation of carotenoids as natural colorants and also for applications in human and animal health. While microbial and other non-plant systems have been successfully used, plant modification eliminates need for expensive bioreactors and offers economically feasible opportunities for less developed nations for production of nutraceuticals and other chemical products. 

From this view, attempts have been directed at the development and improvement of biotechnological processes for the production of carotenoids on an industrial scale. Current successes using mutation methods and molecular engineering techniques carried out over recent years have not only answered some fundamental questions related to pigment formation but also enabled the construction of new microbial varieties that can synthesize unusual carotene metabolites. Elucidation of these mechanisms represents a challenging and potentially rewarding subject for further research and may finally allow us to move from empirical technology to predictable... 

Many yield improvement approaches involve metabolic engineering steps that are devoted to existing plant specialty ingredients like vitamin E (9JO), carotenoids (1IJ2) and flavors and aromas (13). Pathway engineering thereby may involve both plant enzymes as well as prokaryotic and eukaryotic microbial enzymes. These nutritional and dietetic specialties have no bulk feedstock potential, but improvements in terpenoid and isoprenoid biosynthesis may pave the way for the future production of industrial polyisoprenoids like latex and rubber in crops (14). 

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