Review Hidrolisis Biomasa Lignoselulosa Untuk Xilitol

Xilitol adalah gula alkohol dengan lima atom karbon. Gula ini digunakan sebagai pemanis industri pangan dan makanan, karena memiliki karakter yang menguntungkan. Meskipun xilitol diproduksi secara industri oleh reduksi kimia D-xilosa yang berasal dari hidrolisat hemiselulosa, metode produksi ini tidak ekonomis karena persyaratan untuk D-xilosa murni, suhu tinggi, dan tekanan tinggi. Oleh karena itu, produksi xilitol melalui pendekatan bioteknologi dengan bantuan mikroorganisme menjadi fokus sebagai metode yang ekonomis dan ramah lingkungan. Selain itu, untuk meningkatkan produksi bio-xilitol, strain mikroorganisme telah mengalami strategi modifikasi genetik. Review ini menjelaskan upaya produksi xilitol dari biomasa lignoselulasa, proses perlakuan biomasa, dan mikroorganisme yang berperan dalam fermentasi xilitolAbstractXylitol is a sugar alcohol with five atoms of C. This sugar is used as a sweetener in the food industry and confectionary, because it has a favorable character. Although xylitol is produced industrially by the chemical reduction of D-xylose derived from hemicellulose hydrolyzate, this production method is not economical because of the requirements for pure D-xylose, high temperature, and high pressure. Therefore, the production of xylitol with a biotechnological approach with the help of microorganisms becomes the focus as an economical and environmentally friendly method. In addition, to increase bio-xylitol production, strains of microorganisms have undergone genetic modification strategies. This review article describes the latest advances made in the production of xylitol from lignocellulase biomass, biomass treatment processes, and microorganisms that play a role in xylitol fermentation.

Optimized Bioconversion of Xylose Derived from Pre-Treated Crop Residues into Xylitol by Using Candida boidinii

Crop residues can serve as low-cost feedstocks for microbial production of xylitol, which offers many advantages over the commonly used chemical process. However, enhancing the efficiency of xylitol fermentation is still a barrier to industrial implementation. In this study, the effects of oxygen transfer rate (OTR) (1.1, 2.1, 3.1 mmol O2/(L × h)) and initial xylose concentration (30, 55, 80 g/L) on xylitol production of Candida boidinii NCAIM Y.01308 on xylose medium were investigated and optimised by response surface methodology, and xylitol fermentations were performed on xylose-rich hydrolysates of wheat bran and rice straw. High values of maximum xylitol yields (58–63%) were achieved at low initial xylose concentration (20–30 g/L) and OTR values (1.1–1.5 mmol O2/(L × h)). The highest value for maximum xylitol productivity (0.96 g/(L × h)) was predicted at 71 g/L initial xylose and 2.7 mmol O2/(L × h) OTR. Maximum xylitol yield and productivity obtained on wheat bran hydrolysate were 60% and 0.58 g/(L × h), respectively. On detoxified and supplemented hydrolysate of rice straw, maximum xylitol yield and productivity of 30% and 0.19 g/(L × h) were achieved. This study revealed the terms affecting the xylitol production by C. boidinii and provided validated models to predict the achievable xylitol yields and productivities under different conditions. Efficient pre-treatments for xylose-rich hydrolysates from rice straw and wheat bran were selected. Fermentation using wheat bran hydrolysate and C. boidinii under optimized condition is proved as a promising method for biotechnological xylitol production.