Repeated-batch Cultivation of Encapsulated Monascus purpureus by Polyelectrolyte Complex for Natural Pigment Production

In general,productions of natural pigment in submerged microorganism culture were much less than that in solid-state fermentation,because the solid-state culture can provide a support carrier for the mycelium. To improve natural pigment production,the cultivation of Monascus purpureus in submerged encapsulated cell was investigated. Monascus purpureus immobilized in polyelectrolyte complex(PEC) microcapsules,which were pre-pared by sodium cellulose sulphate(NaCS) and poly-dimethyl-diallyl-ammonium chloride(PDMDAAC),was a good substitute for submerged cell culture because it mimicked the solid-state environment. The repeated-batch process with encapsulated cells was studied in flasks and a bubble column. The results indicated that the bubble column was more suitable for the encapsulation culture than the shaking flasks because of its good mass transfer performance and minor shear stress on cells. Owing to the protection of the microcapsule's membrane,Monascus purpureus in microcapsules increased approximately three times over that in free cell culture with negligible cell leakage to the medium. The pigment production in the bubble column finally reached 3.82(OD500) ,which was two times higher than in free cell culture. In addition,the duration of each batch was shortened to 15% of that in free cell culture.

Matching Dyeing and Properties of Silk Fabrics with Natural Edible Pigments

The silk fabrics were matching dyed with three natural edible pigments(red rice red,ginger yellow and gardenia blue).By investigating the dyeing rates and lifting properties of these pigments,it was observed that their compatibilities were excellent in the dyeing process:dye dosage 2.5%(omf),mordant alum dosage 2.0%(omf),dyeing temperature 80℃and dyeing time 40 min.The silk fabrics dyed with secondary colors exhibited vibrant and vivid color owing to the remarkable lightness and chroma of ginger yellow.However,gardenia blue exhibited multiple absorption peaks in the visible light range,resulting in significantly lower lightness and chroma for the silk fabrics dyed with tertiary colors,thus making it suitable only for matte-colored fabrics with low chroma levels.In addition,the silk fabrics dyed with these three pigments had a color fastness that exceeded grade 3 in resistance to perspiration,soap washing and light exposure,indicating acceptable wearing properties.The dyeing process described in this research exhibited a wide range of potential applications in matching dyeing of protein-based textiles with natural colorants.

Biotechnological Potential of Carotenoids Produced by Extremophilic Microorganisms and Application Prospects for the Cosmetics Industry

Carotenoids are isoprenoid pigments used in food, chemical, textile, pharmaceutical, and cosmetic industries. They act not only as dyes and provitamins A but also have antioxidants, photoprotective, antimicrobial properties, among others. This class of pigment can be obtained traditionally by plants or chemical synthesis, but they have some disadvantages. In recent years, search for alternative sources has been an important strategy for the carotenoid industries. Microbial synthesis is an alternative that has shown good yields, speed, and reduced production costs. Hostile environments, such as the Caatinga domain, represent an interesting source of microorganisms that produce biomolecules, especially carotenoids, because of oxidative stress caused by sunlight. Thus, this region has been attracting the attention of the scientific community and industry for the use of these organisms in the production of carotenoids and applications in cosmetic products;since these compounds have interesting antioxidant and photoprotective properties. In this review, general characteristics of carotenoids, sources of production, industrial applicability, and commercialization will be discussed, as well as perspectives on the production of carotenoids from microorganisms isolated from the Caatinga and their application in anti-UV products.

Improvement of betanin biosynthesis in Saccharomyces cerevisiae by metabolic engineering

Betanin is a member of natural pigment betacyanins family and has extensive application in the food industry as an important natural red food colorant.Its relatively inefficient production in nature however hampers access to this phytochemicals through traditional crop-based manufacturing.Microbial bioproduction therefore represents an attractive alternative.Here,we present the construction of a Saccharomyces cerevisiae strain for betanin production.Through minimizing metabolic crosstalk,screening and modifying biosynthetic enzymes,enhancing pathway flux and optimizing fermentation conditions,a final titer of betanin of 28.7 mg/L was achieved from glucose at 25℃ in baffled shake-flask,which is the highest reported titer produced by yeast to our knowledge.This work provides a promising step towards developing synthetic yeast cell factories for de novo biosynthesis of value-added betanin and other betacyanins.

Exploring the influence of crystal packing on the optical-physical property of quercetin-based binary and ternary solid forms

The co-crystallization of quercetin(Qur)with a flexible molecule 4-(4-pyridinyldisulfanyl)pyridine(DPDS)in different solvents and conditions was investigated,yielded five multi-component crystalline phases and characterized with X-ray diffractions and thermal analysis.Although the crystal system of Qur-DPDSMe OH and Qur-DPDS-Dioxane is the same,the desolvation results revealed that Qur-DPDS-Me OH transformed to Qur-DPDS when Me OH solvent molecules escape from the lattice,while Qur-DPDS-Dioxane transformed to Qur-DPDS-II through a similar process,which is same with Qur-DPDS-THF.These two cocrystal polymorphs Qur-DPDS and Qur-DPDS-II obey an enantiotropic relationship.Moreover,the formation of cocrystal solvates improves the packing efficiency of crystals.Crystal structure analysis showed that hydrogen bonds and conformations of the corresponding parent molecules play a major role in molecular assembly and crystal packing patterns,thus bring different physicochemical properties.Finally,the fluorescence spectra and quantum-chemical calculations were carried out to explore the difference in the optical-physical properties.