Xylitol, as an alternative low calorie sweetener is well accepted in formulations of various confectioneries and healthcare products. Worldwide it is industrially produced by catalytic hydrogenation of pure d-xylose solution under high temperature and pressure. Biotechnological xylitol production is a potentially attractive replacement for chemical process, as it occurs under much milder process conditions and can be based on sugar mixtures derived from low-cost industrial and agri-waste. However, microbial fermentation route of xylitol production is not so far practiced industrially. This review highlights the challenges and prospects of biotechnological xylitol production considering possible genetic modifications of fermenting microorganisms and various aspects of industrial bioprocessing and product downstreaming.

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Several efforts have been made during the last three decades to develop successful lignocellulose-based technologies for the production of fuels and chemicals. However, such technologies still seemed to be emerging, because of the high technical risks involved and huge capital investments. This paper describes a holistic approach toward utilization of sugar cane bagasse as lignocellulosic feedstock into fuel (ethanol), chemical (furfural), and energy (electricity), using a biorefinery approach instead of co-generation. The proposed scheme could be integrated with existing sugar or paper mills, where the availability of biomass feedstock is in abundance. Fermentable sugar components (xylose and glucose) from sugar cane bagasse have been extracted employing acid hydrolysis and enzymatic saccharification. Recovery and reuse of saccharifying enzyme was a major process advantage. The pentose fraction was efficiently utilized for yeast biomass generation and furfural production. High-temperature fermentation of a hexose stream by thermophilic yeast Kluyveromyces sp. IIPE453 (MTCC 5314) with cell recycle produced ethanol with an overall yield of 88% ± 0.05% and a productivity of 0.76 ± 0.02 g/L h–1. A complete material balance on two consecutive process cycles, each starting with 1 kg of feedstock, resulted in an overall yield of 366 mL of ethanol, 149 g of furfural, and 0.30 kW of electricity.