Identification and potential biotechnological application of yeast isolates in the UNESCO-MIRCEN biotechnological yeast culture collection of the University of the Free State
Motaung, Thabiso Eric
English: As the initiative for establishing a yeast culture collection began in the early 1980’s in the department of Microbial, Biochemical and Food Biotechnology, research pertaining to the identification of isolates became the main focus. Yeasts such as Candida shehatae and Pichia stipitis claimed potential applications in the fermentation industry and received the most research attention. This research area and others reflected the potential of the culture collection as one of the sources of microbial diversity. As a result, this granted this culture collection a Microbial Resources Centre by the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 1996. Isolation, preservation, identification and determination of taxanomic affinities of yeasts are some of the important aspects of this culture collection in addition to others such as bioprospecting and elucidation of biotechnological applications of strains. As a general practice, these isolates must be identified reliably and rapidly using techniques such as polymerase chain reaction (PCR) and sequencing of the ribosomal DNA. Polymerase chain reaction (PCR) and sequencing of the ribosomal DNA was mainly used in this study to identify isolates present in the UNESCO-MIRCEN Biotechnological Yeast Culture Collection. Ribosomal DNA was amplified and sequenced, followed by analysis of sequence data that was searched against available sequences on National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/). In the case of new species, verification of novelty was performed by sequencing the internal transcribed spacers and doing phylogenetic analysis based on multigenic approach. New species were assigned to their phylogenetic groups and described using standardized traditional techniques. It was apparent from this study that using molecular identification methods, the number of identified ascomycetes and basidiomycetes as well as yeast-like taxa, with possible applications in the industrial, clinical, pharmaceutical, environmental and agricultural settings can be rapidly identified in great numbers. In this study, three basidiomycete strains representing new species in the genus Cryptococcus, with potential applications in cyanide bioremediation, were identified and described. These strains represent a new species which form part of a small group of yeasts (including Cryptococcus humicolus strain) with the ability to utilize inorganic cyanide as sole carbon and nitrogen source. Some of the applications and importance of strains representing known ascomycetes, basidiomycetes and yeast-like taxa are also highlighted here. Not only was the identification of isolates achieved in this study, but also full description of new yeasts present in the UNESCO-MIRCEN Biotechnological Yeast Culture Collection with possible applications in bioremediation. However, the applications of species such as Trichosporon africanensis sp. nov. will be elucidated elsewhere.
Afrikaans: Die inisiatief vir die stigting van 'n giskultuurversameling in die Departement Mikrobiese,Biochemiese en Voedselbiotegnologie het begin in die vroeë 1980's. Navorsing met betrekking tot die identifisering van isolate was die hooffokus. Vir giste soos Candida shehatae en Pichia stipitis is moontlike toepassings in die fermentasie industrie bewys en hulle het dus die meeste navorsingsaandag ontvang. Hierdie en ander navorsing weerspieël die potensiaal van die kultuurversameling as een van die bronne van mikrobiese diversiteit. As gevolg hiervan, ontvang hierdie kultuur versameling ‘Microbial Resources Centre’ status in 1996, toegeken deur die Verenigde Nasies se Opvoedkundige, Wetenskaplike en Kulturele Organisasie (UNESCO). Isolasie, identifikasie en bepaling van taksonomiese verwantskappe van giste is sommige van die belangrike funksies van die kultuurversameling, tesame met ander soos bioprospektering en bepaling van biotegnologiese toepassings van isolate. As deel van algemene praktyke moet die isolate betroubaar en vinnig geïdentifiseer ward d.m.v. tegnieke soos polimerase kettingreaksie (PKR) en bepaling van basispaaropeenvolging van die ribosomale DNS. Polimerase kettingreaksie (PKR) en basispaar-opeenvolgingbepaling van die ribosomale DNA is hoofsaaklik gebruik in hierdie studie om isolate te identifiseer wat teenwoordig is in die UNESCO-MIRCEN biotegnologiese kultuurversameling. Die basispaar-opeenvolging van die ribosomale DNA is bepaal, gevolg deur die analise van data deur veregelykende studies met beskikbare data vanaf National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov). Potensiële nuwe spesies is 135 bevestig deur die volgordebepaling van die ITS gebied asook filogenetiese analise. Nuwe spesies is toegeken aan hulle filogenetiese groepe en beskryf deur gebruik te maak van tradisionele tegnieke. Dit was duidelik uit hierdie studie dat met molekulêre identifikasie metodes die getal van geïdentifiseerde askomisete en basidiomisete sowel as gis-agtige taksa, met moontlike toepassings in die nywerheid, kliniese, farmaseutiese, omgewings- en landbou gebiede, verder verhoog kan word. Drie basidiomiseet isolate wat ‘n nuwe spesie in die genus Cryptococcus, met moontlike toepassing in bioremediëring, verteenwoording, is geïdentifiseer en beskryf in hierdie studie. Hierdie isolate is deel van 'n klein groepie van giste (insluitend Cryptococcus humicolus) wat oor die vermoë beskik om anorganiese sianied as enigste koolstof- en stikstofbron te benut. Sommige van die toepassings van bekende askomisete, basidiomisete en gis-agtige taksa word ook uitgelig in hierdie studie. Nie net was die identifisering van verskeie isolate bereik in hierdie studie nie, maar ook die volledige beskrywing van die nuwe giste teenwoordig in die UNESCOMIRCEN biotegnologiese gis versameling met moontlike toepassings in bioremediëring. Die toepassing van spesies soos Trichosporon africanensis sp. nov sal elders aangespreek word.
Masters Degrees (Microbial, Biochemical and Food Biotechnology)
Oxylipins in automictic yeast life cycles ﻿
Heterologous expression of cytochrome P450 monooxygenases in different ascomycetous yeasts ﻿
Theron, Chrispian William (University of the Free State, 2012-07)
Cytochrome P450 monooxygenases (P450) are a diverse, ubiquitous family of important enzymes which catalyze a variety of activities. Their outstanding abilities to hydroxylate non-activated hydrocarbons make them attractive ...