Method for concentrating a cell suspension comprising a mucilaginous biomass of oleaginous yeasts

Patent metadata

Field	Value
Publication number	US-2018223248-A1
Application number	US-201615749824-A
Country	US
Kind code	A1
Filing date	Aug 5, 2016
Priority date	Aug 6, 2015
Publication date	Aug 9, 2018
Grant date	—

Abstract

A method for concentrating, in order to favour the subsequent extraction process of intracellular lipids, a cell suspension containing a biomass of oleaginous yeasts fermented in fermentation broth under conditions that allow the intracellular accumulation of lipids, where the biomass contains significant quantities of mucilaginous material. The method includes:
a) cultivating the oleaginous yeasts in a fermentation broth to obtain a cell suspension containing the mucilaginous biomass;
b) subjecting the cell suspension obtained from a) to heat treatment, at a temperature between 95° C. and 120° C. and to acid treatment, to obtain a treated cell suspension containing the mucilaginous biomass containing intact oleaginous yeast cells; and
c) concentrating the treated cell suspension obtained from b), by removing at least part of the fermentation broth to obtain a concentrated cell suspension.

First claim

1 . A method for concentrating a cell suspension comprising a mucilaginous biomass of oleaginous yeasts, the method comprising:
a) cultivating oleaginous yeasts in a fermentation broth to obtain a cell suspension comprising the mucilaginous biomass; b) subjecting the cell suspension obtained from a) to heat treatment, at a temperature comprised between 95° C. and 120° C. and to acid treatment, to obtain a treated cell suspension comprising the mucilaginous biomass comprising intact oleaginous yeast cells; and c) concentrating the treated cell suspension obtained from b), comprising removing at least part of the fermentation broth to obtain a concentrated cell suspension.

2 . The method according to claim 1 , wherein in b), the heat treatment is preceded by the acid treatment.

3 . The method according to claim 1 , wherein the oleaginous yeasts are selected from the group consisting of the genera Yarrowia, Candida, Cryptococcus, Trichosporon, Trigonopsis, Torulopsis, Lipomyces, Pichia, Rhodotorula, Rhodosporidium , and consortia thereof.

4 . The method according to claim 1 , wherein the yeasts accumulate lipids in an amount of 25% or higher, of their dry weight.

5 . The method according to claim 1 , wherein the fermentation broth derives from hydrolysis of lignocellulosic biomasses.

6 . The method according to claim 1 , wherein the heat treatment is carried out at a temperature comprised in the range between 100° C. and 110° C.

7 . The method according to claim 1 , wherein the heat treatment is carried out for a time comprised between 3 and 12 hours.

8 . The method according to claim 1 , wherein following the acid treatment, the pH of the cell suspension is comprised in the range between 1.5 and 6.0.

9 . The method according to claim 1 , wherein the acid treatment is carried out by adding an organic or an inorganic Brønsted acid.

10 . The method according to claim 9 , wherein the acid is selected from the group comprising acetic acid, hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, hydrofluoric acid, hydrobromic acid, lactic acid, formic acid, propionic acid, and mixtures thereof.

11 . The method according to claim 1 , wherein the c) concentrating of the cell suspension is carried out by spontaneous sedimentation or gravity, siphoning, vacuum evaporation, lyophilization, flocculation, microfiltration or centrifugation.

12 . The method according to claim 1 , wherein in c), following the removing of at least part of the fermentation broth, the biomass concentration in the obtained cell suspension is comprised between 19.0% dw and 35.0% dw.

Assignees

• Eni Spa

Inventors

• Bortolo Rossella
• Bianchi Daniele

Classifications

• C12N1/16 Primary

  Yeasts; Culture media therefor · CPC title

• C12P19/00

  Preparation of compounds containing saccharide radicals (ketoaldonic acids C12P7/58) · CPC title

• C12N1/02

  Separating microorganisms from their culture media · CPC title

• Y02E50/10

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

• C12N1/005

  after treatment of microbial biomass not covered by C12N1/02 - C12N1/08 · CPC title