Locally isolated yeasts from Malaysia: identification, phylogenetic study and characterization

Area of Science:

• Microbiology
• Biotechnology
• Molecular Biology

Background:

• Yeasts are widely utilized as expression hosts in various biotechnological applications.
• A need exists for novel yeast expression systems to meet evolving molecular cloning demands.
• Environmental screening can yield new yeast species with unique properties.

Purpose of the Study:

• To screen and identify novel yeast isolates from diverse environmental sources.
• To characterize these isolates for their potential as expression hosts and sources of enzymes.
• To develop a new yeast-vector system for molecular cloning.

Main Methods:

• Yeast isolation from environmental samples.
• Identification using ribosomal DNA (rDNA) Internal Transcribed Spacer (ITS) sequencing and phylogenetic analysis (MEGA4).
• Morphological and biochemical characterization.
• Determination of antibiotic resistance markers (Geneticin, Zeocin).
• Screening for lipolytic activity at different temperatures (30°C and 70°C).

Main Results:

• One isolate (WB) was identified as a new species in the order Saccharomycetales.
• Other isolates were identified as Pichia sp., Issatchenkia sp., and Hanseniaspora sp.
• Thermostable lipase activity was detected in isolates RT (0.6 U/mg) and R1 (0.1 U/mg).
• Specific antibiotic resistance markers were determined for each isolate.

Conclusions:

• A novel yeast species (WB) was discovered, suitable for developing a new yeast-vector system using phleomycin or geneticin resistance markers.
• Isolates RT and R1 represent potential novel sources for thermostable lipase production.
• This study expands the repertoire of yeast expression systems and enzyme discovery.