Lipid Accumulation in lipomyces starkeyi cultured in glucose media and sago effluent

Biodiesel production is a promlsmg alternative for the rapid depletion of non-renewable resources. Utilization of waste residues, agricultural waste and feedstock for production of biodiesel are being implemented due to their potential as replacement for conventional diesel and burning fuels. Oleaginous fungi such as Rhodosporidium sp., Lipomyces sp., and Rhodotorula sp. can be used to hydrolyse these materials and turning them into usable biodiesel. In this project, Lipomyces starkeyi (L. starkeyi) was utilized to compare its performance between two different carbon sources, glucose and sago effluent. Natural sago effluent contain starch, another form of carbon source. Glucose was tested at 2.5% (w/v). Optimum growth ofL. starkeyi was detected at 120 hour. The highest biomass production were recorded at 9.63 giL at 144 h by glucose substrate while only 7.40 giL was produced at 144 h when L. starkeyi utilizes sago effluent. The amount of carbon sources consumed per time were determined by using phenol-sulphuric test. From the lipid extraction stage, glucose substrate can yield about 1.83 giL lipid at 144 h while sago effluent only manages to yield 1.20 giL lipid at 144 h. From this data, L. starkeyi that consumes 2.5% glucose can produce 19.0% of its dry biomass into lipid and when sago effluent was used as the substrate, it can yield 16.2% of its dry biomass. In conclusion, 2.5% glucose is a better substrate in culturing L. starkeyi for lipid production rather than using sago effluent

Lipid accumulation in Lipomyces starkeyi mutants cultured in sago media

With the imminent depletion of natural resources, the search for alternatives for diesel has been an ongoing issue in the scientific world. Biodiesel feedstock, such as microbial oil, can be generated from fungi, yeast and algae. However, suitable environment must be provided to ensure optimal growth for efficient production of microbial oil. In this study, two different growth media, yeast malt broth (YMB) and Wild medium were tested for the growth of Lipomyces starkeyi ATCC 12659 and its mutant strains. The mutant strains tested were L. starkeyi MV-01 and L. starkeyi MV-05. L. starkeyi ATCC 12659 produced 8.62 g/L biomass in YMB and 8.51 g/L in Wild media (1.3% difference). A significantly higher yield was recorded for L. starkeyi MV-01 when grown in YMB (9.16 g/L), compared to Wild media (6.44 g/L). As for L. starkeyi MV-05, a lower biomass yield was recorded when grown in YMB (9.62 g/L) than when grown in Wild medium (11.23 g/L). L. starkeyi ATCC 12659 was found to accumulate lipid up to 27.78% (w/w) of its biomass at 8.07 g/L. L. starkeyi MV-01 accumulated lipid at 22.46% (w/w) of its biomass at 7.82 g/L and L. starkeyi MV-05 showed a peak lipid accumulation of 25.89% (w/w) at 8.60 g/L. When grown in sago effluent, L. starkeyi ATCC 12659 efficiently hydrolyzed starch to lipid at 35.04% (w/w) (9.47 g/L) of its dry biomass. L. starkeyi MV-01 was able to produce lipid at 33.62% (w/w) (8.03 g/L) of its dry biomass while L. starkeyi MV-05 converted starch to lipid at 34.11% (w/w) at 9.80 g/L dry biomass. Further studies that focuses on optimizing the cultivation conditions such as the types of carbon sources, carbon to nitrogen ratio, aeration inside the fermentation broth, pH and temperature can be conducted as these attributes greatly affect the microbial lipid yield. These include can greatly. In conclusion, parental strain L. starkeyi showed the highest amount of lipid accumulated when compared with its mutant strains for both sago starch and sago effluent substrate

Isolation, identification and diversity of oleaginous yeasts from Kuching, Sarawak, Malaysia

Vincent M, Hung MC, Baran PRM, Azahari AS, Adeni DSA. 2018. Isolation, identification and diversity of oleaginous yeasts from Kuching, Sarawak, Malaysia. Biodiversitas 19: 1266-1272. The present study was performed to isolate, identify and determine the diversity of oleaginous yeasts from various sources in Kuching, Sarawak (Malaysia). Microscopic observations via light and scanning electron microscope (SEM) indicated that the yeast isolates were in sizes ranging from 2-3 µm in width and 4-8 µm in length, typical of most unicellular ascomycotic fungi. Polymerase Chain Reaction (PCR) and molecular identification performed on the yeast isolates, targeting the D1/D2 region of the 26S rDNA, identified 6 yeast species from the 21 isolates, namely Pichia manshurica (5/21), Candida krusei (8/21), Candida parapsilosis (1/21), Pichia guilliermondii (2/21), Clavispora lusitaniae (1/21) and Kluyveromyces marxianus (4/21). All 21 yeast isolates accumulated intracellular lipids when grown in nitrogen-limited medium, as tested via Sudan IV staining. The present study is the first to document the production of lipids bodies in C. krusei, C. parapsilosis, and C. lusitaniae. Further investigations to assess the growth kinetics, lipid production efficiencies and lipids profiles of these oleaginous yeasts may provide insights into the possible utilization of these isolates for a variety of scientific, technical and industrial applications

Growth Kinetics of Ethidium Bromide Mutagenized Lipomyces starkeyi Strains

Micky Vincent1,*, Latifah Suali1, Afizul Safwan Azahari1, Patricia Rowena Mark Baran1, Elexson Nillian1, Lesley Maurice Bilung

Growth Kinetics of Ethidium Bromide Mutagenized Lipomyces starkeyi Strains

Yeast and growth and biomass production are greatly influenced by the length of the incubation period during cultivation. Therefore, this study was conducted to investigate the growth kinetics of five Lipomyces starkeyi strains as determined by biomass production. The five L. starkeyi strains, namely L. starkeyi ATCC 12659, L. starkeyi MV-1, L. starkeyi MV-4, L. starkeyi MV-5 and L. starkeyi MV-8, were inoculated in sterilized Yeast Malt broth, and, incubated for 192 hr at ambient temperature. Biomass yields were assessed and calculated gravimetrically every 24 hr. Results indicated that the optimal biomass production of L. starkeyi ATCC 12659, L. starkeyi MV-1, L. starkeyi MV-4, L. starkeyi MV-5 and L. starkeyi MV-8 were at 120, 168, 144, 168 and 120 hr, with the concentrations of 6.64, 6.43, 9.78, 11.23 and 8.56 g/L, respectively. These results indicate that each L. starkeyi strain requires specific incubation period for the optimum production of fungal biomass. Therefore, by cultivating each L. starkeyi strain at the predetermined incubation period, biomass yields could significantly be improved for further downstream applications such as single cell protein and lipid production