Screening, identification and optimization of lipase production by a yeast isolated from a tree canopy fern in Mt. Makiling Forest Reserve, Philippines

• Main Authors: Paet, Joseph Martin Q., Querubin, Florabelle D., Legaspi, Charisse Leanne B., Vilela, Julianne A., Tolentino, Jarel Elgin M., Paguio, Angelito A., Jr., Maloles, Johnry S., Zarate, Jocelyn T., Elegado, Francisco B.
• Format: text
• Published: Animo Repository 2018
• Subjects: Lipase; Yeast fungi—Philippines; Yeast fungi—Biotechnology—Philippines; Biology; Biotechnology
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/11572
• Institution: De La Salle University

Lipases (triacylglycerol acylhydrolases, E.C. 3.1.1.3) are enzymes generally used in several industrial applications. This study aimed to screen lipase-producing yeast isolates obtained from Makiling Forest Reserve (MFR), Philippines and to optimize conditions required for the mass production of the enzyme. From the 144 isolates, B1-7 showed the highest lipase activity in both solid and liquid selection media (7.6 EAI and 0.082 U/mL · min activity, respectively). Molecular identification through ITS amplification and phenotypic characterization revealed the putative identity of isolate as Cryptococcus flavescens. Response Surface Method (Box- Behnken Design), suggested that the optimum conditions for maximum lipase production in liquid medium (0.66 U/mL · min) were 5.0 Carbon to Nitrogen ratio (C:N), pH 6.0 and 0.5% inducer. Lipase activity was shown to be significantly affected by the interaction between C: N and inducer (p = 0.010) and inducer alone (p = 0.040). After a 72h fed-batch fermentation experiment, the obtained lipase activity was 0.10 U/mL · min, which was 6-fold lower than expected yield indicating other factors (e.g. oxygen saturation) affecting lipase production. Lipase activity and biomass were also found to be negatively correlated (r = -0.405) suggesting that lipase production did not depend on the available cell population. Lastly, total sugar concentration remained constant implying that the degradative products of lipase were used as the carbon source for cell growth. In conclusion, C. flavescens from MFR with further production optimization can be utilized for mass lipase production.