Non-sterile fermentation of bioethanol

• US 8,496,980 B2
• Filed: 03/29/2011
• Issued: 07/30/2013
• Est. Priority Date: 12/21/2007
• Status: Expired due to Fees

• Current Assignee: Inbicon A/S
• Original Assignee: Inbicon A/S
• Inventors: Larsen, Jan
• Primary Examiner(s): Tate, Chris R
• Application Number:
  US13/074,011
• Publication Number:
  US 20110171708A1
• Time in Patent Office: 854 Days
• Field of Search: None
• US Class Current: 424/750
• CPC Class Codes: A01N 43/08 with oxygen as the ring hetero atom
• CPC Class Codes: A01N 61/00 Biocides, pest repellants or attractants, or plant growth regulators containing substances of unknown or undetermined composition, e.g. substances characterised only by the mode of action
• CPC Class Codes: A01N 65/00 Biocides, pest repellants or attractants, or plant growth regulators containing material from algae, lichens, bryophyta, multi-cellular fungi or plants, or extracts thereof containing compounds of determined constitution A01N27/00 - A01N59/00
• CPC Class Codes: A01N 65/44 Poaceae or Gramineae [Grass family], e.g. bamboo, lemon grass or citronella grass
• CPC Class Codes: C12N 1/22 Processes using, or culture media containing, cellulose or hydrolysates thereof
• CPC Class Codes: C12P 2201/00 Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis
• CPC Class Codes: C12P 7/06 Ethanol, i.e. non-beverage
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

A range of concentrations exists in which fermentation inhibitors derived from pretreatment of lignocellulosic feed stocks inhibit growth of lactic acid bacteria without affecting fermentive yeast. By optimizing levels of fermentation inhibitors to fall within this range, yeast fermentations of lignocellulosic biomass can be conducted under non-sterile conditions with ethanol yields comparable to those achieved under sterile conditions. Optimised inhibitor levels can be achieved by controlling the water/biomass ratio of a lignocellulosic biomass during and after pretreatment, for example by washing the fiber fraction of a previously pretreated lignocellulosic biomass with a pre-defined amount of fresh water or recycled process solutions. Crude extracts of liquid fraction or process solutions from pretreatment of lignocellulosic biomass can also provide an effective anti-bacterial treatment for first generation starch fermentations.

Claims

1. An anti-bacterial composition for use in first generation bioethanol fermentation and effective against lactic acid bacteria comprising concentrated fermentation inhibitors derived from a liquid fraction, a wash water, or a crude extract of a liquid fraction or wash water, and wherein the composition is obtained from corn stover, wheat straw, rice straw, bagasse, corn fiber, empty fruit bunches or grass that has been subject to steam pretreatment to log severity of at least 3.0, the composition comprising greater than 0.19 g/L 5-HMF, greater than 0.74 g/L furfural, greater than 22 ppm vanillin, greater than 35 ppm ferulic acid, greater than 16 ppm coumaric acid, greater than 11 ppm syrinqic acid, greater than 9 ppm syrinqaldehyde, greater than 4 ppm homovanillic acid, and greater than 4.87 g/L acetate.

2. The antibacterial composition of claim 1, wherein useful C5 sugars have been removed from the composition.

3. The antibacterial composition of claim 1, wherein hazardous or unwanted materials have been removed from the composition.

4. An anti-bacterial composition for use in first generation bioethanol fermentations of primarily starch biomass by yeast and effective against lactic acid bacteria, obtained by a process comprising the steps of:

i) pretreating corn stover, wheat straw, rice straw, bagasse, corn fiber, empty fruit bunches or grass with steam at a log severity index of at least 3.0 in order to obtain a pretreated lignocellulosic biomass;

ii) separating the pretreated biomass into at least a fiber fraction and a liquid fraction;

iii) optionally washing the fiber fraction of the pretreated biomass;

iv) collecting liquid fraction or wash water obtained in step ii) and/or iii);

v) optionally providing crude extract(s) or partially purified crude extract(s) of the liquid fraction or wash water obtained in step iv) in such manner that the crude extract(s) or partially purified crude extract(s) comprise fermentation inhibitors; and

vi) concentrating the liquid fraction obtained in step ii) and/or the crude extract(s) or partially purified crude extract(s) obtained in step v)

wherein the composition comprises greater than 0.19 g/L 5-HMF, greater than 0.74 g/L furfural, greater than 22 ppm vanillin, greater than 35 ppm ferulic acid, greater than 16 ppm coumaric acid, greater than 11 ppm syringic acid, greater than 9 ppm syrinqaldehyde, greater than 4 ppm homovanillic acid, and greater than 4.87 g/L acetate.