The Streptomyces aureofaciens sigF gene encodes a sigma factor. By integrative transformation, via double cross-over, a stable null mutant of sigF gene was obtained. This mutation appeared to have no ...obvious effect on vegetative growth, but affected the late stage of spore maturation. Microscopic examination showed that spores were deformed, and spore wall was thinner, compared with the wild-type spores. The spore pigment of sigF mutant was green, compared to wild-type grey-pink spore pigmentation. The plasmid-born wild-type sigF gene complemented the mutation after transformation of the mutant strain.
Production of Pigments de Carvalho, Júlio Cesar; Soccol, Carlos Ricardo; Babitha, Sumathy ...
Current Developments in Solid-state Fermentation
Book Chapter
There is a marked trend towards the use of natural additives in the food and feed industry. In the case of natural pigments, there is a renewed interest in traditional technologies for the production ...of pigments such as carmine (from insects), annatto and curcuma (from plants) or Monascus (from a fungus). There has also been a lot of research on new alternatives, in the last few decades. Because of the intensive metabolite production that is possible in bioprocesses, there is a high interest in pigment production by fermentation. This chapter describes in brief the importance of natural pigments, presents some of the commercially successful, discusses the potential of other microorganisms for pigment production by SSF, and finally describes aspects of the production of Monascus by solid-state fermentation.
Due to the ecologic niche of Malassezia yeasts, host-specific adaptations are an important issue in their biology. The commensal status of Malassezia yeasts is not clearly distinguished from the ...pathogenic stage, as transition from the one to the other is probably a continuum and not an on/off condition. Part of this pathogenic potential is determined by the activities of the enzymatic systems of Malassezia yeasts. The efficiency with which Malassezia yeasts utilize nutrients on the skin surface and in the sebaceous gland determines the size of their population, and also the quality and quantity of the produced metabolic by-products. This organic material ranges from free fatty acids that apply their action through an irritating or toxic effect to highly bioactive indole derivatives that bind to specific cellular receptors and regulate the expression of downstream metabolic pathways. The recently reported genome and secretory proteome of M. globosa and, in part, of M. restricta provide a molecular basis to understand the adaptions of Malassezia yeasts to their environment and to identify factors of pathogenicity. As many experiments on Malassezia biochemistry and physiology had been performed before the current taxonomy of Malassezia species was developed, and the corresponding strains were not deposited in official fungal collections, the genus name Malassezia will be used to include strains that were categorized as Malassezia furfur (sensu lato), Pityrosporum ovale and Pityrosporum orbiculare (see Chap. 2).
Streptomyces avermitilis has the ability to synthesize a diffusible, brown, melanin-like pigment, a common property among many Streptomyces species. A region of the S. avermitilis chromosome involved ...in the production of this pigment was cloned in Escherichia coli. Production of the brown pigment was attained in E. coli, and is optimal when medium is supplemented with copper ions, tyrosine and IPTG. The cloned S. avermitilis pigment-producing DNA fragment is under the control of the lac promoter carried in the E. coli vector. The gene involved in pigment production could be used as a tool to analyse gene expression in S. avermitilis, and as an alternative cloning marker in Streptomyces-Escherichia coli vectors.
Submerged production of Monascus pigments Chu, S.W. (The Chinese University of Hong Kong, Shatin, New Terrorities, Hong Kong); Poon, Y.K
Mycologia,
03/1993, Volume:
85, Issue:
2
Journal Article
Peer reviewed
Monascus pigments are a traditional natural food colorant in China and Japan. We previously found that addition of corn oil to the cultivation medium doubled the pigment yield. Therefore, we tested ...the effect of Tween 80, a watermiscible emulsion of oleic acids, on pigment production. It has been proposed that pigment production was at the expense of conidiogenesis and growth. We examined this hypothesis by performing cytological studies in Monascus purpureus Went.
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