PROCESS FOR MODULATING THE NUTRITIONAL VALUE OF WHOLE STILLAGE AND DISTILLERS PRODUCTS ASSOCIATED THERETO
Fermentation by-products can be used in feed to provide nutrients to animals. The present disclosure concerns a process for modulating the nutritional content in a whole stillage. The process includes fermenting a biomass in the presence of a recombinant lactic acid bacteria (LAB) cell and a yeast with a biomass and recuperating the whole stillage once the fermentation has been completed. The recombinant LAB is capable of expressing one or more first heterologous enzyme for converting the biomass into the fermentation product.
1 . A process of modulating the nutritional content of a whole stillage obtained after the fermentation of a biomass, the process comprising:
(a) contacting a recombinant lactic acid bacteria (LAB) host cell, a yeast and the biomass under conditions to cause the conversion of at least in part of the biomass into a fermentation product and to obtain a fermented biomass comprising the whole stillage and the fermentation product; and
(b) separating the whole stillage from the fermentation product;
wherein the recombinant LAB host cell is capable of expressing one or more first heterologous enzyme for converting the biomass into the fermentation product; and
wherein the whole stillage obtained after step (b) has a different nutritional content than a control whole stillage submitted to step (a) in the absence of the recombinant LAB host cell.
2 . The process of claim 1 , wherein the whole stillage has, when compared to the control whole stillage:
an increase in protein content;
a different amino acid profile;
an increase in fiber content;
an increase in lipid content; and/or
when the biomass comprises starch, a decrease in starch content.
3 . The process of claim 1 , wherein the biomass comprises or is obtained from corn and/or the fermentation product comprises or is ethanol.
4 . The process of claim 3 , wherein the one or more first heterologous enzyme comprises a polypeptide having pyruvate decarboxylase activity and/or a polypeptide having alcohol dehydrogenase activity and the recombinant LAB host cell has a decreased lactate dehydrogenase activity when compared to a corresponding native LAB host cell.
5 . The process of claim 1 , wherein the biomass comprises one or more bacteriocin and the recombinant LAB host cell expresses (i) one or more second polypeptide conferring immunity to the one or more bacteriocin and/or (ii) the one or more bacteriocin.
6 . The process of claim 1 , wherein the biomass comprises one or more antibiotic and the recombinant LAB host cell expresses one or more third heterologous polypeptide conferring resistance to the one or more antibiotic or is adapted to be resistant to the antibiotic. The process of claim 1 , wherein the recombinant LAB host cell expresses one or more fourth polypeptide having proteolytic activity, wherein the one or more fourth polypeptide is a native polypeptide or a heterologous polypeptide.
8 . The process of claim 1 , wherein the recombinant LAB host cell expresses one or more fifth polypeptide involved in the metabolism of one or more amino acid, wherein the one or more fifth polypeptide is a native polypeptide or a heterologous polypeptide.
9 . The process of claim 8 , wherein the one or more amino acid comprises glutamate/gamma-amino butyrate.
10 . The process of claim 9 , wherein the one or more fifth polypeptide comprises:
a glutamate decarboxylase; and/or
a glutamate/gamma-amino butyrate (GABA) transporter.
11 . The process of claim 1 , wherein the recombinant LAB host cell is from the genus Lactobacillus sp. and/or from the species Lactobacillus paracasei.
12 . The process of claim 1 , wherein the yeast is a recombinant yeast host cell, from the genus Saccharomyces sp and/or from the species Saccharomyces cerevisiae.
13 . The process of claim 1 , comprising, at step (b), distilling the fermented biomass to remove the fermentation product from the whole stillage.
14 . The process of claim 1 further comprising centrifuging the whole stillage to separate a thin stillage from a wet cake.
15 . The process of claim 14 , further comprising:
formulating the wet cake in distillers wet grains (DWG);
drying the wet cake to obtain distillers dried grains (DDG); and/or
evaporating the thin stillage to obtain a syrup.
16 . The process of claim 15 , further comprising:
adding the syrup to the wet cake to obtain distillers wet grains with solubles (DWGS);
drying the syrup to obtain dried solubles (DS); and/or
further comprising drying the DWGS to obtain distillers dried grains with solubles (DDGS).
17 . A composition comprising (i) whole stillage obtainable or obtained by the process of claim 1 and (ii) a component of the recombinant LAB host cell.
18 . Distillers wet grains (DWG), distillers dried grains (DDG) or a syrup obtainable or obtained by the process of claim 15 and comprising a component of the recombinant LAB host cell.
19 . Distillers wet grains with solubles (DWGS), dried solubles (DS) Distillers dried grains and solubles (DDGS) obtainable or obtained by the process of claim 16 and comprising a component of the recombinant LAB host cell.