Process for xylitol production from xylose

Patent metadata

Field	Value
Publication number	US-11618907-B2
Application number	US-202117394811-A
Country	US
Kind code	B2
Filing date	Aug 5, 2021
Priority date	Aug 7, 2020
Publication date	Apr 4, 2023
Grant date	Apr 4, 2023

Abstract

The present invention discloses a process of xylitol production from pure xylose, xylose containing liquid extract from the acid pretreated biomass (LEPB) and co-production of ethanol and xylitol from dilute acid pretreated lignocellulosic biomass by natural S. cerevisiae DBT-IOC S24 (MTCC25086). The present invention also discloses a process of xylitol production wherein a thermo and inhibitor tolerant S. cerevisiae DBT-IOC S24 (MTCC25086) natural strain has been induced to produce xylitol from xylose at defined process parameters using xylose containing diluted acid pretreated biomass as well as from xylose containing synthetic media in presence of glucose, lignocelluloses biomass derived xylitol inducer maintaining aeration at 1VVM and pH at 5.0 in the medium.

First claim

What is claimed is:

1. A process of xylitol production from pure xylose, wherein said process comprises the steps of:
a) inoculating a natural thermo- and inhibitor tolerant yeast strain having concentration of 10 mM inducer in a synthetic fermentation medium containing 4% xylose, 1% glucose, 0.2% of yeast extract and 0.1% peptone and incubating at a temperature of 37° C. and at 200 rpm;
b) adding 290-360 mg glucose and 8.0-12.0 mg inducer in every 15 min interval to one liter of fermented broth containing synthetic media as described above, after 6 h of fermentation;
c) maintaining aeration at 1VVM and pH at 5.0 in the medium; and
d) obtaining xylitol yield of 99%.

2. The process as claimed in claim 1 , wherein said natural thermo and inhibitor tolerant yeast strain is Saccharomyces cerevisiae DBT-IOC S24 (MTCC25086).

3. The process as claimed in claim 1 , wherein 300 mg glucose and 10 mg inducer are added in every 15 min interval to one liter of fermented broth containing synthetic media, after 6 h of fermentation.

4. The process as claimed in claim 1 , wherein said lignocelluloses biomass derived xylitol inducer is selected from furfural or HMF.

5. The process as claimed in claim 1 , wherein said sugars comprises glucose and xylose in a combination ratio of 1:4.

6. The process as claimed in claim 1 , wherein the fermentation is carried out for 120-140 h at 37° C. for obtaining xylitol with a yield of 0.89 g/g.

7. A process of xylitol production from liquid extract from dilute acid pretreated biomass (LEPB), wherein said process comprises steps of:
a) inoculating a natural thermo and inhibitor tolerant yeast strain ( Saccharomyces cerevisiae DBT-IOC S24 (MTCC25086)) at concentration of 2 g/L cell to liquid extract from dilute acid pretreated biomass containing 4% xylose, 1% glucose, major inducers selected from furfural or HMF;
b) maintaining aeration to 1VVM and pH at 5.0 during fermentation process;
c) Obtaining xylitol yield of 99%.

8. The process as claimed in claim 7 , wherein the fermentation is carried out for 120-140 h at 37° C. for obtaining xylitol with a yield of 0.89 g/g.

9. The process as claimed in claim 7 , wherein said liquid extract from dilute acid pretreated biomass (LEPB) contains 4% xylose, 1% glucose, major inducers selected from furfural or HMF.

10. The process as claimed in claim 9 , wherein concentration of inducers ranges between 0.5 to 1.2 g/L depending on severity of pre-treated biomass.

11. A two-step fermentation process for co-production of xylitol and ethanol from acid pretreated biomass, wherein the process comprises steps of:
diluting acid pretreated biomass using natural thermo and inhibitor tolerant yeast Saccharomyces cerevisiae DBT-IOC S24 (MTCC25086), strain;
adding cellulase enzyme 0.3 FPU/TS to 15% biomass solid loading at the initial stage of process to release glucose sugar during the process which facilitate xylose uptake by Saccharomyces cerevisiae DBT-IOC S24 (MTCC25086) and maintaining proper yeast cell growth;
obtaining xylitol conversion yield up to 99% of theoretical yield;
subjecting the remaining biomass for enzymatically hydrolysis by adding cellulase at 2.0 FPU/gTS at 50° C. for 31 h; followed by fermentation for ethanol production by inoculating yeast Saccharomyces cerevisiae DBT-IOC S24 (MTCC25086) from glucose sugar;
obtaining 21 g/L ethanol concentration at 37° C. by Saccharomyces cerevisiae DBT-IOC S24 (MTCC25086), after final fermentation.

Assignees

• Indian Oil Corp Ltd
• Dept Of Biotechnology India

Inventors

• Sharma Ajay Kumar
• Swain Manas Ranjan
• Singh Ajit
• Mathur Anshu Shankar
• Gupta Ravi Prakash
• Puri Suresh Kumar
• RAMAKUMAR Sankara Sri Venkata

Classifications

• C12P7/18 Primary

  polyhydric · CPC title

• C12P19/02

  Monosaccharides (2-ketogulonic acid C12P7/60) · CPC title

• C12P2203/00

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

• Y02E50/10

  Biofuels, e.g. bio-diesel · CPC title

• C12P7/10

  substrate containing cellulosic material · CPC title