Plant sweet and yeast MSF transporter capable of transporting different sugars simultaneously
The present disclosure provides genetically engineered microorganisms for the simultaneous fermentation of pentose and hexose sugars, for example, glucose and xylose. The microorganisms can be modified to express AtSWEET polypeptides, LST1 polypeptides, mutants thereof, homologs thereof or combinations thereof. Also provided are methods of co-fermenting hexose and pentose sugars, methods of increasing the conversion of lignocellulosic biomass via microbial fermentation, and methods of generating biofuel.
1 . A recombinant yeast comprising one or more heterologous polynucleotides encoding an Arabidopsis thaliana SWEET7 (AtSWEET7) transporter polypeptide comprising 90% or more sequence identity to SEQ ID NO: 3, wherein an Asn amino acid at position 145 (Asn145) of the AtSWEET7 transporter is substituted with a Ser amino acid (Asn145Ser substitution), an Ala amino acid at position 175 (Ala175) is substituted with a Phe amino acid (Ala175Phe substitution), or both the Asn145 and the Ala175 are respectively substituted with a Ser and a Phe (Asn145Ser substitution and an Ala175Phe substitution).
2 . The recombinant yeast of claim 1 , wherein the recombinant yeast does not express endogenous or heterologous hexose transporter HXT1-7, and does not express heterologous or endogenous Gal2 transporter.
3 . The recombinant yeast of claim 1 , wherein the recombinant yeast is selected from Saccharomyceraceae sp., Saccharomyces cerevisiae, Saccharomyces pastorianus, Saccharomyces beticus, Saccharomyces fermentati, Saccharomyces paradoxus, Saccharomyces uvarum Saccharomyces bay anus; Schizosaccharomyces sp., Schizosaccharomyces pombe, Schizosaccharomyces japonicus, Schizosaccharomyces octosporus, Schizosaccharomyces cryophilus, Torulaspora sp., Torulaspora delbrueckii, Kluyveromyces sp., Kluyveromyces marxianus, Pichia sp., Pichia stipitis, Pichia pastoris, Pichia angusta, Zygosaccharomyces sp., Zygosaccharomyces bailii, Brettanomyces sp., Brettanomyces inter medius, Brettanomyces bruxellensis, Brettanomyces anomalus, Brettanomyces custersianus, Brettanomyces naardenensis, Brettanomyces nanus, Dekkera bruxellensis, Dekkera anomala; Metschmkowia sp., Issatchenkia sp., Issatchenkia orientalis, Kloeckera sp. Kloeckera apiculate, Aureobasidium sp., Aureobasidium pullulans , and Corynebacterium glutamicum.
4 . The recombinant yeast of claim 1 , wherein the recombinant yeast is Saccharomyces cerevisiae.
5 . The recombinant yeast of claim 1 , wherein the recombinant yeast has improved sugar co-utilization of two or more sugars as compared to a control yeast.
6 . The recombinant yeast of claim 5 , wherein the two or more sugars are a first sugar that is glucose and a second sugar that is selected from galactose, lactose, arabinose, mannose, sucrose, fructose, xylobiose, cellobiose, xylose, rhamnose, 4-deoxy-L-erythro-5-hexoseulose uronate, maltose, cellodextrins, or combinations thereof.
7 . The recombinant yeast of claim 1 , further comprising a heterologous polynucleotide encoding a RT04_11075 or RT04_13042 putative glucose transporter and/or a heterologous polynucleotide encoding a RT04_13731 or RT04_10452 putative xylose transporter.
8 . A method for co-utilization of two or more different sugars in a fermentation reaction comprising contacting the recombinant yeast of claim 1 with two or more different sugars under fermentation conditions such that the two or more different sugars are co-utilized at an improved rate as compared to a control yeast.
9 . The method of claim 8 , wherein the two or more different sugars are a first sugar that is glucose and a second sugar that is selected from galactose, lactose, arabinose, mannose, sucrose, fructose, xylobiose, cellobiose, xylose, rhamnose, 4-deoxy-L-erythro-5-hexoseulose uronate, maltose, cellodextrins, or a combination thereof.
10 . A method of producing ethanol comprising contacting the recombinant yeast of claim 1 with two or more different sugars under fermentation conditions such that the two of more sugars are co-utilized and ethanol is produced.
11 . The method of claim 10 , wherein the two or more different sugars are present in a lignocellulosic biomass.
12 . The method of claim 11 , wherein the lignocellulosic biomass comprises glucose, xylose, galactose, fructose, sucrose, xylodextrin, cellobiose, arabinose, mannose, lactose, or combinations thereof.
13 . A bioreactor for continuous conversion of lignocellulosic biomass into biofuel comprising the recombinant yeast of claim 1 .
14 . The recombinant yeast of claim 5 , wherein the two or more sugars are glucose and xylose.
15 . The recombinant yeast of claim 1 , wherein the Arabidopsis thaliana SWEET7 (AtSWEET7) transporter polypeptide comprises SEQ ID NO:3.