title: Heterologous expression of a thermophilic esterase in Kluyveromyces yeasts.
abstract: In the present work, a thermophilic esterase from Thermus thermophilus HB27 was cloned into Kluyveromyces marxianus and into Kluyveromyces lactis using two different expression systems, yielding four recombinant strains. K. lactis showed the highest esterase expression levels (294 units per gram dry cell weight, with 65% of cell-bound enzyme) using an episomal system with the PGK promoter and terminator from Saccharomyces cerevisiae combined with the K. lactis k1 secretion signal. K. marxianus showed higher secretion efficiency of the heterologous esterase (56.9 units per gram dry cell weight, with 34% of cell-bound enzyme) than K. lactis. Hydrolytic activities for the heterologous esterases were maximum at pH values between 8.0 and 9.0 for both yeast species and at temperatures of 50 °C and 45 °C for K. marxianus and K. lactis, respectively. When compared to previously published data on this same esterase produced in the original host or in S. cerevisiae, our results indicate that Kluyveromyces yeasts can be considered good hosts for the heterologous secretion of thermophilic esterases, which have a potential application in biodiesel production or in resolving racemates.
authors.affiliation: Department of Chemical Engineering, University of São Paulo, C.P. 61548, 05424-970 São Paulo, SP, Brazil. saul@bio4.com.br
authors.forename: Saul Nitsche
authors.initials: SN
authors.lastname: Rocha
authors.forename: José
authors.initials: J
authors.lastname: Abrahão-Neto
authors.forename: María Esperanza
authors.initials: ME
authors.lastname: Cerdán
authors.forename: Andreas Karoly
authors.initials: AK
authors.lastname: Gombert
authors.forename: María Isabel
authors.initials: MI
authors.lastname: González-Siso
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004795:Enzyme Stability; D004950:Esterases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D006358:Hot Temperature; D007716:Kluyveromyces / Q000235:genetics* / Q000378:metabolism; D015202:Protein Engineering; D016963:Thermus thermophilus / Q000737:chemistry / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D004950:Esterases