Artbestämning och karaktärisering av laktosväxande vildjäst från Nigeria
Typ
Examensarbete på kandidatnivå
Program
Publicerad
2022
Författare
Good, Johanna
Bellot Avendaño, Gelmy
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
During cheese production, whey is a residual product, containing disaccharide lactose and other
nutrients and minerals. Large quantities of whey must be disposed of yearly, which becomes costly
since it requires further processing. The possibility of using microorganisms to convert this cheap
and available resource into valuable bioproducts is an attractive approach. However, few known
yeasts can perform this task without extensive genomic engineering. The discovery of yeast species
that naturally produce valuable biochemicals could increase the value of whey in the
industry. Therefore, from a large collection of wild Nigerian yeast isolates, our research sought to
identify new yeast species that can grow on lactose.
This was done by identifying species with DNA sequence data from a collection of ~6000 wild
Nigerian yeast strains, were ~230 was found to grow on lactose. One representative isolate from 15
selected species were chosen for cultivating, HPLC-analysis, and literature review. The species were
selected based on findings in literature such as usage in industry, bioproduct formation and biohazard
level. The selected species include Apiotrichum mycotoxinovorans, Candida orthopsilosis, Candida
pseudointermedia, Clavispora lusitaniae, Cutaneotrichosporon curvatum, Cyberlindnera fabianii,
Kodamaea ohmeri, Meyerozyma caribbica, Meyerozyma carpophila, Moesziomyces antarcticus,
Papiliotrema flavescens, Rhodotorula mucilaginosa, Trichosporon insectorum, Vishniacozyma
taibaiensis and Yarrowia lipolytica.
The literature research of this study revealed that all yeast species may have industrial potential, but
more research is needed, especially for C. pseudointermedia, M. carpophila and V. taibaiensis, for
which information was lacking. Species that produced fatty lipids deemed of special interest, due to
the potential for future use in biotechnology. The result from the cultivation showed that half of the
species grew well on lactose medium, which was backed up by the HPLC analysis. M. antarcticus
was the only species which had greater growth in lactose medium than in glucose medium, and which
also, shown trough the HPLC analysis, produced products that differed from other species.
Although a few species showed good potential, further research is needed to determine if the species
is suitable future industrial usage.