Process for the detoxification of lignocellulosic hydrolysate and its use in synthesizing xylitol

Patent metadata

Field	Value
Publication number	US-12516356-B2
Application number	US-202118256012-A
Country	US
Kind code	B2
Filing date	Dec 6, 2021
Priority date	Dec 4, 2020
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

The present invention relates to a process for the detoxification and concentration of xylose rich biomass derived liquid hydrolysate and its application as a substrate for the synthesis of crystalline and pure xylitol.

First claim

We claim:

1 . A process for the simultaneous detoxification and concentration of xylose rich biomass derived liquid hydrolysate using a custom-designed glass chamber, wherein said process comprises the steps of:
i. hydrolysing the biomass for the pretreatment by using dilute sulphuric acid, wherein the ratio of biomass and sulphuric acid is 1:8 at a temperature in the range of 138° C.-140° C. with a holding time period in the range of 85-90 minutes at 100-120 rpm to obtain a biomass slurry; ii. passing the discharged biomass slurry as obtained in step i) through a squeezer for solid-liquid separation to obtain a xylose rich liquid solution; iii. keeping the xylose rich liquid solution as obtained in step ii) in a solar concentrator and exposing to sunlight at a temperature in the range of 25° C. to 45° C. for a period in the range of 47-48 hours to obtain the substantially furfural free xylose rich acid hydrolysed detoxified hydrolysate, wherein, the said detoxification and concentration process resulted in removal of ˜95% of furfural in the acid hydrolysed xylose rich lignocellulosic composition.

2 . The process as claimed in claim 1 , wherein said detoxification and concentration process resulted in removal of ˜99% of furfural in the acid hydrolysed xylose rich lignocellulosic composition.

3 . A process for the production of crystalline xylitol from detoxified and concentrated lignocellulosic biomass obtained by the process as claimed in claim 1 , in the presence of a whole-cell biocatalyst, wherein the process comprises the steps of:
a) concentrating the dotoxified and concentrated xylose rich biomass derived liquid hydrolysate broth further by using a rotary vacuum evaporator to achieve a xylose concentration of 66, 100 and 150 g/L; b) monitoring the xylitol production from concentrated biomass hydrolysate (at varying xylose concentration) obtained at step a) by Pichia caribicca MTCC 5703 strain in a bioreactor with a supervisory control and a data acquisition (SCADA) system; c) controlling the fermentation parameters by maintaining the biomass obtained at step b) at a temperature in the range of 28-30° C., agitation at 150-200 rpm, and the pH of the system at 6.0-6.5; d) allowing the cells to settle down of the biomass obtained at step c) after fermentation; e) siphoning out the xylitol rich broth obtained at step d) from the fermenter and decolorizing by activated carbon treatment (5% w/v); f) filtering and concentrating the filtrate with a xylitol content of 8-12% by weight obtained at step e) in a rotary evaporator at 80° C. under vacuum (0.5 atm) to achieve a xylitol content of 80-90% by weight; g) cooling the filtrate obtained at step f) gradually from 60° C. to 25° C. over a period of about 1-2 hours while controlling the temperature and then keeping at a temperature in the range of ˜20° C. to 0° C. for 5 days to complete the crystallization of xylitol; h) separating and drying the crystals to obtain crystalline xylitol.

4 . The process as claimed in claim 3 , wherein said produced xylitol from lignocellulosic biomass hydrolysate is with high yields and selectivity, wherein the maximum yield is 0.87 g/g with a product selectivity of >96%.

5 . The process as claimed in claim 3 , wherein said process results in ˜85% xylitol recovery from the broth in the form of crystals with a degree of purity of >96.9%.

6 . The process as claimed in claim 3 , wherein the Xylitol crystals demonstrated no toxic effect on HepG2 cell lines when assayed for cytotoxicity studies.

Assignees

• Council Scient Ind Res

Inventors

• Dasgupta Diptarka
• Prabhune Asmita Ashutosh
• More Snehal Vijay
• Ghosh Debashish
• Thallada Bhaskar
• Ray Anjan
• Sidana Arushdeep

Classifications

• C12P2203/00

  Fermentation products obtained from optionally pretreated or hydrolyzed cellulosic or lignocellulosic material as the carbon source · CPC title

• C12P2201/00

  Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis · CPC title

• C12R2001/84

  Pichia · CPC title

• C12P7/18 Primary

  polyhydric · CPC title