Production of Xylitol from d-Xylose by Overexpression of Xylose Reductase in Osmotolerant Yeast Candida glycerinogenes WL2002-5

Abstract

Efficient bioconversion of D-xylose into various biochemicals is critical for the developing lignocelluloses application. In this study, we compared D-xylose utilization in Candida glycerinogenes WL2002-5 transformants expressing xylose reductase (XYL1) in D-xylose metabolism. C. glycerinogenes WL2002-5 expressing XYL1 from Schefferomyces stipitis can produce xylitol. Xylitol production by the recombinant strains was evaluated using a xylitol fermentation medium with glucose as a co-substrate. As glucose was found to be an insufficient co-substrate, various carbon sources were screened for efficient cofactor regeneration, and glycerol was found to be the best co-substrate. The effects of glycerol on the xylitol production rate by a xylose reductase gene (XYL1)-overexpressed mutant of C. glycerinogenes WL2002-5 were investigated. The XYL1-overexpressed mutant produced xylitol from D-xylose using glycerol as a co-substrate for cell growth and NAD (P) H regeneration: 100 g/L D-xylose was completely converted into xylitol when at least 20 g/L glycerol was used as a co-substrate. XYL1 overexpressed mutant grown on glycerol as co-substrate accumulated 2.1-fold increased xylitol concentration over those cells grown on glucose as co-substrate. XYL1 overexpressed mutant produced xylitol with a volumetric productivity of 0.83 g/L/h, and a xylitol yield of 98 % xylose. Recombinant yeast strains obtained in this study are promising candidates for xylitol production. This is the first report of XYL1 gene overexpression of C. glycerinogenes WL2002-5 for enhancing the efficiency of xylitol production.

Production of Caffeic Acid with Co-fermentation of Xylose and Glucose by Multi-modular Engineering in Candida glycerinogenes

“…Endogenous genes for xylose utilization, including genes for xylose reductase (XYL1) and xylose kinase (XKS1), are present in C. glycerinogenes . In our previous study, the strain CGWT was fermented in YPX medium for 84 h. Moreover, the OD 600 reached 2.8, but the xylose concentration did not decrease, which indicated that xylose was not utilized (Figure S4).…”

Review Hidrolisis Biomasa Lignoselulosa Untuk Xilitol

“…Pemilihan ragi untuk fermentasi merupakan hal yang penting dalam proses fermentasi xilitol. Beberapa strain ragi digunakan untuk produksi xilitol, yaitu Candida tropicalis (Misra dan Raghuwanshi., 2012;Rao et al, 2006), C. guilliermondii (Arruda et al, 2017), C. glycerinogenes (Zhang et al, 2015), C. mogii (Tochampa et al, 2005), Rhodotorula mucilaginosa (Vajzovic et al, 2012), Pichia pastoris (Cheng et al, 2014), Yamadazyma ubonensis (Junyapate et al, 2014), Scheffersomyces amazonensis (Cadete et al, 2016), dan Meyerozyma caribbica Y67 (Saputra et al, 2020). Saccharomyces cerevisiaestrain asli tidak dapat memfermentasi gula xilosa untuk membentuk xilitol, namun dengan memasukkan gen penyandi xilosa reduktase (XR) dari Scheffersomyces (Pichia) stipites, maka isolat hasil rekayasa dapat memanfaatkan xilosa untuk produksi xilitol (Oh et al, 2013).…”

Biosynthesis of Xylitol from Glucose: Microorganism, Key Enzymes and Genetically Engineered Strains

“…Several natural xylose-fermenting yeasts, such as Candida sp., Pichia stipites, Aspergillus carbonarius, Debaryomyces nepalensis, Schefferomyce stipitis and Pachysolen tannophilus, can use this co-substrate to generate xylitol [3,7,8]. Usually, Candida genus has strong ability of producing xylitol, such as Candida tropicalis and Candida guilliermondii being able to convert 90% xylose to xylitol in 24 h. However, these natural yeasts require a well-controlled supply of oxygen and are sensitive to ethanol levels, which limit their use [3]. Other species including P. stipitis and Saccharamyces cerevisiae, which are widely used as host strains, also have strong ability of production xylitol.…”

“…At present, xylitol was mainly produced by chemical method of acidification and hydrogenation and semi-biological method of microbial fermentation of hemicellulose hydrolysate. In the semi-biological method, several natural xylose-fermenting yeasts can convert D-xylose to xylitol through reduction by a Nicotinamide Adenine Dinucleotide (Phosphate) (reduced) (NAD (P) H)-dependent xylose reductase (XR) [3]. Both of the methods rely on the hydrolysis and purification of D-xylose from hemicellulose-xylan hydrolysates.…”