Bioconversion of lignocellulosic biomass to xylitol: An overview.

Wine is a complex beverage, comprising thousands of metabolites that are produced through the action of a plethora of yeasts and bacteria during fermentation of grape must. These microbial communities originate in the vineyard and the winery and reflect the influence of several factors including grape variety, geographical location, climate, vineyard spraying, technological practices, processing stage and season (pre-harvest, harvest, post-harvest). Vineyard and winery microbial communities have the potential to participate during fermentation and influence wine flavour and aroma. Therefore, there is an enormous interest in isolating and characterising these communities, particularly non-Saccharomyces yeast species to increase wine flavour diversity, while also exploting regional signature microbial populations to enhance regionality. In this review we describe the role and relevance of the main non-Saccharomyces yeast species found in vineyards and wineries. This includes the latest reports covering the application of these species for winemaking; and the biotechnological characteristics and potential applications of non-Saccharomyces species in other areas. In particular, we focus attention on the species for which molecular and genomic tools and resources are available for study. Copyright © 2016 John Wiley & Sons, Ltd.

Yeasts found in vineyards and wineries.

Xylitol is a white crystalline, amorphous sugar alcohol and low-calorie sweetener. Xylitol prevents demineralization of teeth and bones, otitis media infection, respiratory tract infections, inflammation and cancer progression. NADPH generated in xylitol metabolism aid in the treatment of glucose-6-phosphate deficiency-associated hemolytic anemia. Moreover, it has a negligible effect on blood glucose and plasma insulin levels due to its unique metabolism. Its diverse applications in pharmaceuticals, cosmetics, food and polymer industries fueled its market growth and made it one of the top 12 bio-products. Recently, xylitol has also been used as a drug carrier due to its high permeability and non-toxic nature. However, it become a challenge to fulfil the rapidly increasing market demand of xylitol. Xylitol is present in fruit and vegetables, but at very low concentrations, which is not adequate to satisfy the consumer demand. With the passage of time, other methods including chemical catalysis, microbial and enzymatic biotransformation, have also been developed for its large-scale production. Nevertheless, large scale production still suffers from high cost of production. In this review, we summarize some alternative approaches and recent advancements that significantly improve the yield and lower the cost of production.

https://www.mdpi.com/2304-8158/9/11/1592/pdf

Biological and Pharmacological Potential of Xylitol: A Molecular Insight of Unique Metabolism.

Random mutagenesis of Clostridium butyricum strain and optimization of biosynthesis process for enhanced production of 1,3-propanediol.

We are pleased to dedicate this paper to Dr Julian E Davies. Julian is a giant among microbial biochemists. He began his professional career as an organic chemistry PhD student at Nottingham University, moved on to a postdoctoral fellowship at Columbia University, then became a lecturer at the University of Manchester, followed by a fellowship in microbial biochemistry at Harvard Medical School. In 1965, he studied genetics at the Pasteur Institute, and 2 years later joined the University of Wisconsin in the Department of Biochemistry. He later became part of Biogen as Research Director and then President. After Biogen, Julian became Chair of the Department of Microbiology at the University of British Columbia in Vancouver, Canada, where he has contributed in a major way to the reputation of this department for many years. He also served as an Adjunct Professor at the University of Geneva. Among Julian's areas of study and accomplishment are fungal toxins including α-sarcin, chemical synthesis of triterpenes, mode of action of streptomycin and other aminoglycoside antibiotics, biochemical mechanisms of antibiotic resistance in clinical isolates of bacteria harboring resistance plasmids, their origins and evolution, secondary metabolism of microorganisms, structure and function of bacterial ribosomes, antibiotic resistance mutations in yeast ribosomes, cloning of resistance genes from an antibiotic-producing microbe, gene cloning for industrial purposes, engineering of herbicide resistance in useful crops, bleomycin-resistance gene in clinical isolates of Staphylococcus aureus and many other topics. He has been an excellent teacher, lecturing in both English and French around the world, and has organized international courses. Julian has also served on the NIH study sections, as Editor for several international journals, and was one of the founders of the journal Plasmid. We expect the impact of Julian's accomplishments to continue into the future.

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Production of valuable compounds by molds and yeasts.

A new strain producing high yield of d-arabitol was isolated from hyperosmotic environments and the ITS rDNA sequencing analysis revealed it as Zygosaccharomyces rouxii. In addition, using a pH control and repeated-batch fermentation strategy in a 5-L reactor, the maximum yield and the highest volumetric productivity of d-arabitol were 93.48 ± 2.79 g/L and 1.143 g/L h, respectively. Volumetric productivity was successfully improved from 0.86 to 1.143 g/L h, which was increased by 32.9 % after 72 h of fermentation. Z. rouxii JM-C46 has potential to be used for d-arabitol and xylitol production from glucose via d-arabitol route.

Enhanced d-arabitol production by Zygosaccharomyces rouxii JM-C46: isolation of strains and process of repeated-batch fermentation

Enhanced xylitol production: Expression of xylitol dehydrogenase from Gluconobacter oxydans and mixed culture of resting cell.

Microbial and Enzymatic Process for Xylitol Production from D-glucose

Xylitol is the first rare sugar that has global market because of its excellent properties. Considering its superiority to chemosynthesis, biosynthesis of xylitol became hot issue in recent studies. The production of xylitol from glucose experienced a development from three-step process to two-step process, or even only one-step process. The microbial and enzymatic process involving key enzymes, molecular cloning and expression and transgenic bacteria construction is introduced in this paper. This study may provide novel thought to explore new resource for better control of biological reaction conditions and obtainment of higher xylitol yield.

Microbial Bioconversion Process of Glucose for the Production of Xylitol

The invention relates to a 1,3-propylene glycol genetically engineered bacterium and a method for producing 1,3-propylene glycol by mixing and converting the 1,3-propylene glycol genetically engineered bacterium, and belongs to the field of biotechnology. A PCR (Polymerase Chain Reaction) technology is used for cloning a 1,3-propylene glycol oxidation-reduction enzyme dhaT gene derived from lactobacillus brevis (Lactobacillibrevis CICC6239) so as to construct a genetically engineered strain E.coli-pSE-dhaT which is capable of efficiently and actively expressing the 1,3-propylene glycol oxidation-reduction enzyme (1,3-propanedioldehydrogenase, PDOR). The experiment proves that the enzymatic activity of the 1,3-propylene glycol oxidation-reduction enzyme expressed by the recombinant bacteria is increased by 16 times; the engineered bacterium and the lactobacillus brevis are mixed, stand still and are converted to glycerin, and the conversation rate from the glycerin to the 1,3-propylene glycol can reach 80.6%.

Jing Lin

Papers

Enhanced d-arabitol production by Zygosaccharomyces rouxii JM-C46: isolation of strains and process of repeated-batch fermentation

Enhanced xylitol production: Expression of xylitol dehydrogenase from Gluconobacter oxydans and mixed culture of resting cell.

Microbial and Enzymatic Process for Xylitol Production from D-glucose

Microbial Bioconversion Process of Glucose for the Production of Xylitol

1,3-propylene glycol genetically engineered bacterium and method for producing 1,3-propylene glycol by converting same