Method for preparing sugar, bioethanol or microbial metabolite from lignocellulosic biomass

Patent metadata

Field	Value
Publication number	US-2016298142-A1
Application number	US-201414991209-A
Country	US
Kind code	A1
Filing date	Jun 9, 2014
Priority date	Jul 9, 2013
Publication date	Oct 13, 2016
Grant date	—

Abstract

The present invention relates to a method for preparing bioethanol from lignocellulosic biomass. The method of the present invention is capable of: minimizing the impurity content of an enzymatic saccharification raw material, by extracting biomass using hot water, before pretreatment, and removing extractable substances such as inorganic salts; suppressing, to the greatest extent, the production of overdecomposition products of sugar, by pretreating the biomass, from which the hot water extractable substances have been removed, in a condition for maximizing xylan yield; preparing fermentable sugar at a low cost, without washing a pretreated solid obtained from subsequent solid-liquid separation, but by only concentrating a sugar solution obtained after enzymatic saccharification, using a separation film; and preparing bioethanol therefrom in high yield.

First claim

1 . A method for producing bioethanol from lignocellulosic biomass, the method comprising the steps of:
1) adding water to coarsely ground or powdery lignocellulosic biomass and heating at 50 to 140° C. for 1 to 60 minutes, followed by dehydration; 2) adding water to a solid obtained at the step 1 and performing liquid hot water pretreatment at 170 to 210° C. for 1 minute to 30 minutes; 3) obtaining a solid including a small amount of liquid from the liquid hot water pretreatment product obtained at the step 2 by solid-liquid separation; 4) performing enzymatic hydrolysis of the solid obtained at the step 3 by a cellulase enzyme complex at 45 to 55° C.; 5) recovering a sugar solution from the saccharification product obtained at the step 4 through repeated processes of solid-liquid separation and extraction; 6) performing filtration, concentration and impurity removal of the sugar solution obtained at the step 5 to obtain fermentable sugar; and 7) fermenting the fermentable sugar obtained at the step 6 using an ethanologen.

2 . The method for producing bioethanol from lignocellulosic biomass according to claim 1 , wherein a weight ratio of the coarsely ground or powdery lignocellulosic biomass and the water at the step 1 is from 1:4 to 1:20.

3 . The method for producing bioethanol from lignocellulosic biomass according to claim 1 , wherein the step 1 is performed at 80 to 105° C.

4 . The method for producing bioethanol from lignocellulosic biomass according to claim 1 , wherein the temperature and reaction time at the step 2 is within a range in which the yield of hemicellulose sugar is at maximum when the enzymatic hydrolysis of the entire pretreatment product obtained from the step 2 is performed.

5 . The method for producing bioethanol from lignocellulosic biomass according to claim 1 , wherein the solid-liquid separation at the step 3 is performed by centrifugal 10 separation, suction filtration or pressure filtration.

6 . The method for producing bioethanol from lignocellulosic biomass according to claim 1 , wherein the solid obtained at the step 3 includes 5 to 30 wt % of pretreated liquid of the total liquid produced by pretreatment.

7 . The method for producing bioethanol from lignocellulosic biomass according to claim 1 , wherein the method does not comprise a separate sterilization treatment process after the step 3.

8 . The method for producing bioethanol from lignocellulosic biomass according to claim 1 , wherein the recovery of the sugar solution at the step 5 is performed by batch-type or continuous centrifugal separation, filter press or screw press.

9 . The method for producing bioethanol from lignocellulosic biomass according to claim 1 , wherein membrane separation technique including a reverse osmosis membrane is applied to filtration, concentration, and impurity removal of the sugar solution at the step 6.

10 . The method for producing bioethanol from lignocellulosic biomass according to claim 1 , wherein the fermentable sugar obtained at the step 6 contains 30% or more of glucose.

11 . The method for producing bioethanol from lignocellulosic biomass according to claim 1 , wherein the ethanologen at the step 7 is selected from the group consisting of Saccharomyces cerevisiae, Escherichia coli, Clostridium beijerinckii, Clostridium acetobutylicum , and Zymomonas mobilis.

12 . A method for producing fermentable sugar from lignocellulosic biomass which acetic acid was removed, the method comprising the steps of:
1) adding water to coarsely ground or powdery lignocellulosic biomass and performing liquid hot water pretreatment, and performing solid-liquid separation of the obtained pretreatment product to obtain a solid; 2) adding an aqueous alkali solution warmed at room temperature to 100° C. or less to the solid obtained at the step 1), mixing them and dehydrating to recover the solid; and 3) adding a cellulose hydrolysis enzyme to the solid obtained at the step 2) to perform enzymatic hydrolysis.

13 . The method according to claim 12 , wherein the liquid hot water pretreatment at the step 1) is performed at 160 to 230° C. for 0.001 to 60 minutes.

14 . The method according to claim 12 , wherein the aqueous alkali solution is prepared to exhibit alkalinity of pH 11 or higher when mixed with the solid obtained at the step 1).

15 . The method according to claim 12 , wherein the aqueous alkali solution is present in an amount 1 to 20 times larger than the total weight of the solid obtained at the step 1).

16 . The method according to claim 12 , wherein the fermentable sugar contains an amount of acetic acid that is ½ or less of an amount of acetic acid in a sugar solution prepared without removing acetic acid after pretreatment.

17 . A method for fermentation of microorganisms using fermentable sugar in which acetic acid was removed, as produced by the method according to claim 12 .

18 . A production method of fermentable sugar having reduced toxicity of acetic acid, the production method comprising the steps of:
1) performing liquid hot water pretreatment of lignocellulosic biomass to produce a pretreatment product for enzymatic hydrolysis; and 2) adding a cellulose hydrolysis enzyme to the pretreatment product obtained at the step 1, and adding an alkali reagent including a base with at least two hydroxyl groups in a molecule, having a dissolution constant (pKa 2 ) of 8.0 or more for a second acetyl group of acetate, to perform enzymatic hydrolysis.

19 . The production method according to claim 18 , wherein the pretreatment product for enzymatic hydrolysis at the step 1) is selected from the group consisting of:
a) both a liquid and a solid obtained by performing liquid hot water pretreatment of lignocellulosic biomass; b) a solid obtained by solid-liquid separation after liquid hot water pretreatment of lignocellulosic biomass; and c) a pretreatment product dehydrated after washing, with water or an aqueous alkali solution, a solid obtained by solid-liquid separation after liquid hot water pretreatment of lignocellulosic biomass.

20 . The production method according to claim 18 , wherein the liquid hot water pretreatment is performed at 160 to 230° C. for 1 to 60 minutes.

21 . The production method according to claim 18 , wherein the base is calcium hydroxide, barium hydroxide or magnesium hydroxide.

22 . The production method according to claim 18 , wherein the alkali reagent is fine powder, an aqueous alkali solution prepared by dissolving a base in water, or a colloidal suspension prepared by fine grinding a base such that the colloidal suspension has an average diameter of 0.001 to 10 μm.

23 . A method for fermentation of microorganisms using fermentable sugar having reduced toxicity of acetic acid produced by the method according to claim 18 .

24 . A method for producing microbial metabolite from lignocellulosic biomass containing starch, the method comprising the steps of:
1) performing liquid hot water pretreatment of ground lignocellulosic biomass containing starch using steam or water under the following condition: a) a temperature range of 170° C. to 230° C.; and b) a reaction time at which the yield of hemicellulose sugar produced at the step 2) is at maximum; 2) saccharifying the entire pretreatment product using cellulase or cellulase enzyme complex without solid-liquid separation; and 3) adding microorganisms to the saccharification product to perform fer

Assignees

• Korea Res Inst Chemical Tech

Inventors

• Yu Ju Hyun
• Jung Chan Duck
• Eom In Yong
• Lee Seung Hwan
• Hong Kyung Sik
• Kim In Chul
• Jegal Jong Geon
• Song Bong Keun

Classifications

• C12P19/02 Primary

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

• C07H1/06

  Separation; Purification · CPC title

• C12P2201/00

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

• C12P7/14 Primary

  Multiple stages of fermentation; Multiple types of microorganisms or re-use of microorganisms · CPC title

• C07H3/02

  Monosaccharides · CPC title