The thermotolerantyeast Hansenulapolymorpha fermentsglucoseandxylosetoethanolathigh
temperatures.However, H. polymorpha cannotutilizestarchymaterialsorxylans.Heterologous
amylolyticandxylanolyticenzymeshavetobeexpressedinthisyeasttoprovideforutilizationand
growthonstarchandxylan.Genes SWA2 and GAM1 fromtheyeast Schwanniomyces occidentalis,
encoding a-amylaseandglucoamylase,respectively,wereexpressedin H. polymorpha. Theexpression
wasachievedbyintegrationofthe SWA2 and GAM1 genesunderthestrongconstitutivepromoterofthe
H. polymorpha glyceraldehyde-3-phosphatedehydrogenasegene(HpGAP) into H. polymorpha genome.
Resultingtransformantsacquiredtheabilitytogrowonaminimalmediumcontainingsolublestarchas
a solecarbonsource.Ethanolproductionathigh-temperaturefermentationfromstarchbythe
recombinant strainswasupto10g/L.The XYN2 geneencodingendoxylanaseofthefungus Trichoderma
reseei wasexpressedin H. polymorpha. Co-expressionof xlnD gene codingfor b-xylosidase ofthefungus
Aspergillusniger and the XYN2 gene in H. polymorpha wasachievedbyintegrationofthesegenesunder
controlofthe HpGAP promoter.Resultingtransformantswerecapableofgrowthandalcoholic
fermentationonaminimalmediumsupplementedwithbirchwoodxylanasasolecarbonsourceat
48 1C.
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