Microbial Oil Research Articles

Microbes: A Hidden Treasure of Polyunsaturated Fatty Acids.

Microbes have gained a lot of attention for their potential in producing polyunsaturated fatty acids (PUFAs). PUFAs are gaining scientific interest due to their important health-promoting effects on higher organisms including humans. The current sources of PUFAs (animal and plant) have associated limitations that have led to increased interest in microbial PUFAs as most reliable alternative source. The focus is on increasing the product value of existing oleaginous microbes or discovering new microbes by implementing new biotechnological strategies in order to compete with other sources. The multidisciplinary approaches, including metabolic engineering, high-throughput screening, tapping new microbial sources, genome-mining as well as co-culturing and elicitation for the production of PUFAs, have been considered and discussed in this review. The usage of agro-industrial wastes as alternative low-cost substrates in fermentation for high-value single-cell oil production has also been discussed. Multidisciplinary approaches combined with new technologies may help to uncover new microbial PUFA sources that may have nutraceutical and biotechnological importance.

An Innovative Prosopis cineraria Pod Aqueous Waste as Natural Inhibitor for Enhancing Unsaturated Lipids Production in Yeast Cell Using Banana Peel

Single cell oil (SCO) produced by yeast is an attractive alternative due to higher yield of lipid in a limited space with opportunity for naturally manipulating its quality. In the present study, the banana peel is used as a source of carbon for biotransformation by Rhodotorula mucilaginosa to lipid. Further, the quality and quantity of the lipid are enhanced using discarded aqueous Prosopis cineraria pod extract as a natural inhibitor. Prosopis cineraria aqueous extract was quantified using HPLC to contain phenylpropenoids such as epicatechin (0.068%), gallic acid (0.29%), quercetin (0.34%), epigallocatechin (0.091%), rutin (0.141%), ellagic acid (0.141%), along with glucose (1.22%), and sucrose (2.36%). The sucrose and glucose were isolated from the aqueous extract, and further characterized through NMR and TGA. Hence, this natural inhibitor is found expedient as compared to the chemical inhibitor (statin) in terms of lipid production with desirable quality. It is achieved by inhibitors blocking of yeast competitive mevalonate pathway to promote higher lipid accumulation in the microbial cells. The anti-cholestrolemic activity of this natural inhibitor might be influenced lipid accumulation by blocking the mevalonate pathway. Thus, the reducing sugars as well as phenylpropenoids were worked in synergy to enhance the accumulation of unsaturated lipid in the microbial cells. Phenylpropenoids may inhibit the key enzyme HMG reductase, which controls the mevalonate pathway for ergosterol formation to induce lipid accumulation. This lipid isolation from yeast cell was improved using green solvent viz. liquid-CO2. This liquid-CO2 extract was enriched with unsaturated lipid (46.96%) including ω-fatty acids such as linoleic (17.61%) and linolenic (5.35%). Thus, the SCO is produced using food waste as the source of carbon as well as an inhibitor, and this lipid is treated as natural to find suitable for nutritional purposes.Graphical Abstract

Production of single cell oil by Yarrowia lipolytica JCM 2320 using detoxified desiccated coconut residue hydrolysate.

Nowadays, the replacement of petro-diesel with biodiesel has raised the concern among the community for the utilization of improper feedstocks and the cost involved. However, these issues can be solved by producing single cell oil (SCO) from lignocellulosic biomass hydrolysates by oleaginous microorganisms. This study introduced Yarrowia lipolytica JCM 2320 with a desiccated coconut residue (DCR) hydrolysate (obtained from the 2% dilute sulphuric acid pretreatment) as a carbon source in generating SCO. However, common inhibitors formed during acid pretreatment of biomass such as five-hydroxymethylfurfural (HMF), furfural, acetic acid and levulinic acid resulting from the sugar degradations may have detrimental effects towards the fermentation process. To visualize the effect of inhibitors on Y. lipolytica, an inhibitory study was conducted by adding 0.5–5.0 g/L of potential inhibitors to the YPD (yeast, peptone and D-glucose) medium. It was found that the presence of furfural at 0.5 g/L would increase the lag phase, which beyond that was detrimental to Y. lipolytica. Furthermore, increasing the five-hydroxymethylfurfural (HMF) concentration would increase the lag phase of Y. lipolytica, whereas, for acetic acid and levulinic acid, it showed a negligible effect. Detoxification was hence conducted to remove the potential inhibitors from the DCR hydrolysate prior its utilization in the fermentation. To examine the possibility of using adsorption resins for the detoxification of DCR hydrolysate, five different resins were tested (Amberlite® XAD-4, Amberlite® XAD-7, Amberlite® IR 120, Amberlite® IRA 96 and Amberlite® IRA 402) with five different concentrations of 1%, 3%, 5%, 10% and 15% (w/v), respectively. At resin concentration of 10%, Amberlite® XAD-4 recorded the highest SCO yield, 2.90 ± 0.02 g/L, whereas the control and the conventional overliming detoxification method, recorded only 1.29 ± 0.01 g/L and 1.27 ± 0.02 g/L SCO accumulation, respectively. Moreover, the fatty acid profile of the oil produced was rich in oleic acid (33.60%), linoleic acid (9.90%), and palmitic acid (14.90%), which indicates the potential as a good biodiesel raw material.

Influence of the Sludge Retention Time on Membrane Fouling in an Anaerobic Membrane Bioreactor (AnMBR) Treating Lipid-Rich Dairy Wastewater.

This study evaluated the effects of sludge retention time (SRT) on the membrane filtration performance of an anaerobic membrane bioreactor (AnMBR) fed lipid-rich synthetic dairy wastewater. The membrane filtration performance was evaluated in two AnMBR systems operated at two different SRTs, i.e., 20 and 40 days. For the AnMBR operated at 40 days, SRT exhibited worse membrane filtration performance characterized by operational transmembrane pressures (TMP) exceeding the maximum allowed value and high total resistances to filtration (Rtotal). The sludge in the two reactors evaluated at the different SRTs showed similar sludge filterability properties. However, the sludge in the reactor operated at 40 days SRT was characterized by exhibiting the highest concentrations of: (i) total suspended solids (TSS), (ii) small-sized particles, (iii) extracellular polymeric substances (EPS), (iv) soluble microbial products (SMP), (v) fats, oils and grease (FOG), and (vi) long-chain fatty acids (LCFA). The cake layer resistance was the major contributor to the overall resistance to filtration. The high TSS concentration observed in the AnMBR systems apparently contributed to a less permeable cake layer introducing a negative effect on the membrane filtration performance.

Isolation, molecular identification of lipid-producing Rhodotorula diobovata: optimization of lipid accumulation for biodiesel production

BackgroundThe increased demand for oil and fats to satisfy the ever-increasing human needs has enhanced the research in this field. Single-cell oils or microbial lipids produced by oleaginous microorganisms are being utilized as an alternative to traditional oil sources. Oleaginous yeasts can accumulate lipids above 20% of their biomass when they are grown under controlled conditions. ResultsIn the present study, sixty-five yeasts were isolated from different sources. Using Sudan Black B staining technique, five yeast isolates were selected. Under nitrogen-limited cultivation conditions, the Co1 isolate was the best lipid accumulation potential of 39.79%. Isolate (Co1) was characterized morphologically and identified using the ribosomal DNA internal transcribed spacers regions (rDNA-ITS) from their genomic DNA. The sequence alignment revealed a 99.2% similarity with Rhodotorula diobovata. Under the optimized conditions, Rhodotorula diobovata accumulated lipids up to 45.85% on a dry biomass basis. R. diobovata, when grown on different raw materials, accumulated lipid up to 46.68% on sugar beet molasses medium, and the lipid had a high degree of monounsaturated fatty acids which gives biodiesel better quality. ConclusionsThe data suggest that the potent oleaginous yeast, R. diobovata, together with the use of cheap feedstock raw materials such as sugar beet molasses, can be considered as a promising feedstock for biodiesel production.

In Situ Transesterification of Microbial Biomass for Biolubricant Production Catalyzed by Heteropolyacid Supported on Niobium

Lubricants are substances of the foremost importance in the modern world, as they are essential to the proper functioning of various mechanisms. Most lubricants, however, are still made from petroleum fractions. I light of this, and due to various environmental problems, the search for feasible biolubricants has become essential. This study obtained biolubricants through the in situ transesterification of microbial biomass, containing at least 20 wt% of lipids. The following two distinct biomasses were evaluated: the marine microalgae, Dunaliella salina, and the consortium of microalgae-fungi, Scenedesmus obliquus and Mucor circinelloides. Microbial oil from both biomasses presented a fatty acid profile with high amounts of oleic acid. The oil of D. salina had a lower content of polyunsaturated fatty acids relative to the microbial consortium profile, which indicates that this is a good configuration for increasing biolubricant oxidation resistance. The catalyst used was a Keggin-structure heteropolyacid supported on niobium, H3PMo12O40/Nb2O5, activated at 150 °C, which had high transesterification yields, notwithstanding the feedstocks, which were rich in free fatty acids. The performed transesterification reactions resulted in excellent yields, up to 97.58% and 96.80%, for marine microalgae and the consortium, respectively, after 6 h at 250 °C, with 10 wt% of catalyst (related to the lipid amount). As such, the (H3PMo12O40/Nb2O5) catalyst could become an attractive option for producing biolubricants from microbial biomass.

The influence of different carbon sources on growth and single cell oil production in oleaginous yeasts Apiotrichum brassicae and Pichia kudriavzevii

Oleaginous yeasts offer an interesting possibility for renewable lipid production, since the single cell oil accumulated can be based on a wide range of cheap, waste-derived carbon sources. Here, several short chain carboxylic acids and sugars commonly found in these substrates were assessed as carbon sources for Apiotrichum brassicae and Pichia kudriavzevii. While both strains were able to utilize all carbon sources employed, high volumetric lipid productivities (0.4 g/Lh) and lipid contents (68%) could be reached particularly with acetic acid as carbon source. Odd-numbered volatile fatty acids led to lower productivities and lipid contents, but the lipids contained unusually high proportions of odd-numbered fatty acids (up to 80% of total fatty acids). These fatty acids are rather uncommon in nature and might offer the possibility for various high value applications. In conclusion both strains are able to utilize a wide range of substrates potentially present in waste-derived substrates. Lipid content and volumetric lipid productivity strongly depend on the carbon source, with even-numbered volatile fatty acids resulting in the highest values. For volatile fatty acids in particular, the carbon source also strongly influences the composition of the lipids produced by the yeast strains.

Shear thinning and shear thickening aspects in magnetized 3D cross-nanofluid flow with activation energy and motile microorganisms

Bioconvection has recently become a point of contention in several biotechnological fields that rely on fluids and their physical properties. Bioconvection tends to happen when mixed nanofluids are subjected to elevated and mass transmission. I'm fascinated by the widespread use of bioconvective nanofluids in the construction of microbial fuel cells, microbial oil extraction mechanisms, processing plants, and other applications. Current research looks at the heat and mass transport properties of cross-nanofluid. Effects of stratification for double diffusion are also considered. Variable thickness sheets are increasingly being used in civil engineering, mechanical, aeronautical, and maritime processes and constructions. Flow and heat transfer across stretching surfaces is used in many technical processes, including polymer extrusion, plastic film stretching, food, and paper processing, fiberglass manufacturing, wire drawing, and continuous casting. Primary goal of the ongoing research is to learn about the properties of activation energy, nonlinear thermal radiation, heat sink source, and motile microorganisms of three-dimensional cross nanofluid flow. The bvp4c structure is used to numerically encode the boundary value problem in the MATLAB mathematical code. To retrieve numerical and graphical reports on velocity, thermal, and energy profiles versus the values of the most important physical parameters, graphs and tables were used.

Development and Research Status of Heavy Oil Enhanced Oil Recovery

Heavy oil is an important part of petroleum hydrocarbon energy. With the depletion of conventional crude oil reserves, successful and efficient exploitation of heavy oil resources is becoming increasingly important. This article focuses on the nine relatively mature heavy oil development technologies from the perspectives of the level of understanding of the mechanism and the scale of the mining field: steam huff and puff, steam flooding, steam-assisted gravity drainage (SAGD), in situ combustion, thermochemical combined flooding, multicomponent thermal fluid, polymer flooding, chemical viscosity reduction development, and microbial oil recovery, which are divided into two technical categories: thermal recovery and cold recovery development. The basic development principles are explained, and application examples of the two categories of techniques are provided. It is pointed out that thermal compounding, cold mining development, and nanomaterial applications will be the three development trends in heavy oil development.

Controlling the Formation of Foams in Broth to Promote the Co-Production of Microbial Oil and Exopolysaccharide in Fed-Batch Fermentation

A large amount of foam is generated in the production of microbial oil and exopolysaccharide (EPS) by Sporidiobolus pararoseus JD-2, which causes low efficiency in fermentation. In this study, we aimed to reduce the negative effects of foams on the co-production of oil and EPS by controlling the formation of foams in broth. As we have found, the formation of foams is positively associated with cell growth state, air entrapment, and properties of broth. The efficient foam-control method of adding 0.03% (v/v) of the emulsified polyoxyethylene polyoxypropylene pentaerythritol ether (PPE) and feeding corn steep liquor (CSL) at 8–24 h with speed of 0.02 L/h considerably improved the fermentation performance of S. pararoseus JD-2, and significantly increased the oil and EPS concentrations by 8.7% and 12.9%, respectively. The biomass, oil, and EPS concentrations were further increased using a foam backflow device combined with adding 0.03% (v/v) of the emulsified PPE and feeding CSL at 8–24 h, which reached to 62.3 ± 1.8 g/L, 31.2 ± 0.8 g/L, and 10.9 ± 0.4 g/L, respectively. The effective strategy for controlling the formation of foams in fermentation broth reported here could be used as a technical reference for producing frothing products in fed-batch fermentation.

The oleaginous yeast Pichia manshurica isolated from Lansium domesticum fruit in Thailand and its fatty acid composition of single cell oil

Abstract. Planonth S, Chantarasiri A. 2022. The oleaginous yeast Pichia manshurica isolated from Lansium domesticum fruit in Thailand and its fatty acid composition of single cell oil. Biodiversitas 23: 801-809. Oleaginous microbes can accumulate intracellular lipids or single cell oils (SCOs) in quantities higher than 20% of their biomass. They can be a sustainable alternative to fossil fuels, biofuels, and oleochemicals. Studies concerning efficient oleaginous yeasts isolated from the natural environments remain scarce. Therefore, this study isolated and screened for efficient oleaginous yeasts from the surfaces of longkong fruit (Lansium domesticum) samples in Thailand. Their intracellular SCOs were extracted using an ultrasonic-assisted extraction (UAE) method and quantitatively analyzed. The SCO-accumulating yeasts (produce the amount of SCOs <20 % of their biomass) genetically identified were Candida jaroonii, Meyerozyma caribbica, Kodamaea ohmeri, and Pichia sp., while the oleaginous yeasts (produce the amount of SCOs >20% of their biomass) identified were Pichia manshurica and Hanseniaspora opuntiae. Several isolated yeasts were designated as rare oleaginous microbes. The P. manshurica strain Y2 was considered as the most effective oleaginous yeast with a SCO content of 43.03% (w/w). The fatty acids in the accumulated SCO of this strain were analyzed by gas chromatography (GC) that consisted of palmitic, stearic, oleic, linoleic, and palmitoleic acids. These fatty acids could be further applied in the production of third-generation biodiesel, cocoa butter equivalents, and related high-value oleochemicals.

Single cell oil production from hydrolysates of alkali pre-treated giant reed: High biomass-to-lipid yields with selected yeasts

Single cell oil (SCO) produced by oleaginous yeasts represents an intriguing source for second generation biofuels or other biobased oleochemicals. This study aimed at improving SCO production from giant reed (Arundo donax L.). Five different yeast species were used to evaluate the lipid yield and fatty acids profile obtained in six media prepared with two enzymatic hydrolysates of mild alkali pre-treated giant reed fibers (washed or not after filtration) and variable nitrogen supplementation (three levels). After pre-treatment and hydrolysis, up to 489 ± 9 mg of reducing sugars per g of initial untreated biomass were obtained. C/N ranged widely (38−258) among the different formulated media, depending on both washing and nitrogen supplementation, and strongly affected SCO accumulation by most of the strains. Lipomyces starkeyi, Rhodosporidiobolus azoricus, and Cutaneotrichosporon oleaginosum reached the highest lipid contents (54–68%) and concentrations (4.8–5.6 g/L). The highest lignocellulosic biomass-to-lipid conversions were obtained with C. oleaginosum, R. azoricus, and L. starkeyi (102 ± 9, 95 ± 9, and 89 ± 3 mg of lipids per g of untreated giant reed biomass, respectively). Oleic, palmitic, linoleic, and stearic acid were predominant in the fatty acids profile, similarly to seed oils. In conclusion, hydrolysates derived from the alkali pre-treated biomass of giant reed are suitable to obtain high lipid yields with selected yeasts, to be used for the biobased industry.

Brine and Post-Frying Oil Management in the Fish Processing Industry—A Concept Based on Oleaginous Yeast Culture

Waste management solutions including the valorization of waste materials in biotechnological processes is an important issue needing to be explored. A significant amount of waste is being generated by the food industry. In this study, an attempt was made to utilize two fish industry wastes simultaneously—waste brine and post-frying oil from frying fish fillets in Yarrowia lipolytica culture with high single cell oil synthesis yield. Oxygenation in the culture medium had a positive effect on the biosynthesis efficiency of microbial oil, resulting in the highest content of lipids in yeast cells at the level of 0.431 g/g d.m (dry mass). Y. lipolytica yeast preferentially accumulated oleic acid and linoleic acid, and the high content of linolenic acid, valuable from a nutritional point of view, was also found in microbial oil. This study proved that the use of post-frying rapeseed oil gives a chance to obtain valuable storage lipids in Y. lipolytica yeast cells via ex novo biosynthesis pathway. Furthermore, the wastewater stream could be limited using a waste brine as a solvent in medium preparation, but the brine share should not exceed 30% so as not to inhibit yeast cell growth.

Using Aspergillus ochraceus, a Native Fungus, to Convert Biodiesel-Derived Crude Glycerol to Single Cell Oil for Commercial Applications

Using Aspergillus ochraceus, a Native Fungus, to Convert Biodiesel-Derived Crude Glycerol to Single Cell Oil for Commercial Applications

Production of microbial oils by the oleaginous yeast Rhodotorula graminis S1/2R in a medium based on agro-industrial by-products.

Biodiesel generated by transesterification of triglycerides from renewable sources is a clean form of energy that is currently used in many countries in blends with petrodiesel. It is mainly produced from food-grade vegetable oils obtained from oleaginous crops. High prices of these oils have made the sustainability of biodiesel production questionable. The use of nonedible feedstocks, such as intracellular triglycerides accumulated by oleaginous yeasts, appears as a feasible alternative. However, it has been demonstrated that an economically sustainable production of yeast oil could only be possible if low-cost media based on industrial subproducts, or wastes are used. In this work, we propose intracellular lipids production by a previously selected oleaginous yeast strain in a medium composed only by sugar cane vinasse and crude glycerol. Different culture strategies were studied. The highest biomass and lipid yields were obtained when the yeast R. graminis S1/2R was cultivated in batch without control of dissolved oxygen. The fatty acid methyl esters obtained under these conditions met the specification of international biodiesel standards.

Agroindustrial byproduct-based media in the production of microbial oil rich in oleic acid and carotenoids.

This study focuses on the potential of Rhodotorula mucilaginosa CCT 7688 in simultaneous production of lipids and carotenoids in agroindustrial byproduct-based media and specially aims at establishing a process condition that guarantees high concentrations of both bioproducts, i.e., a carotenoid-rich microbial oil with potential economic value and health benefits attributed to carotenoids and fatty acids. Four different combinations of cultivation modes (batch and fed-batch) and alternative substrates (crude glycerol, sugarcane molasses and corn steep liquor) were tested. The M2-B assay, which comprises the use of an agroindustrial byproduct-based medium without any supplementation (70g L-1 sugarcane molasses and 3.4g L-1 corn steep liquor) and batch mode, was selected as the most promising one to produce both compounds. Total carotenoid production and total lipid content were 1794.2µg L-1 and 43.2% (w/w), respectively, after 144h of cultivation. The fatty acid profile showed predominance of oleic acid (69.9%) and palmitic acid (23.2%). Thus, R. mucilaginosa CCT 7688 may be used in simultaneous production of lipids and carotenoids successfully; its fatty acid profile is similar to that found in olive oil. Both compounds are economically interesting and have great possibility of future commercial applications.

Microbial Consortia Are Needed to Degrade Soil Pollutants.

Soil pollution is one of the most serious environmental problems globally due to the weak self-purification ability, long degradation time, and high cost of cleaning soil pollution. The pollutants in the soil can be transported into the human body through water or dust, causing adverse effects on human health. The latest research has shown that the clean-up of soil pollutants through microbial consortium is a very promising method. This review provides an in-depth discussion on the efficient removal, bio-adsorption, or carbonated precipitation of organic and inorganic pollutants by the microbial consortium, including PAHs, BPS, BPF, crude oil, pyrene, DBP, DOP, TPHP, PHs, butane, DON, TC, Mn, and Cd. In view of the good degradation ability of the consortium compared to single strains, six different synergistic mechanisms and corresponding microorganisms are summarized. The microbial consortium obtains such activities through enhancing synergistic degradation, reducing the accumulation of intermediate products, generating the crude enzyme, and self-regulating, etc. Furthermore, the degradation efficiency of pollutants can be greatly improved by adding chemical materials such as the surfactants Tween 20, Tween 80, and SDS. This review provides insightful information regarding the application of microbial consortia for soil pollutant removal.

Genome-scale metabolic model of oleaginous yeast Papiliotrema laurentii

Oleaginous yeasts are promising candidates as single cell oil (SCO) platforms to meet energy demand due to their high growth rate, easy scaling and the possibility of being cultivated in culture media based on lignocellulosic biomass. The oleaginous yeast Papiliotrema laurentii UFV-1 is able to reach high lipid contents in short periods, besides its composition of fatty acids is suitable in terms of quality standards required for biodiesel production. However, little is known about the regulation of its metabolism. We present here the first genome-scale metabolic reconstruction of P. laurentii, papla-GEM. The reconstruction was based on homology to another oleaginous yeast and the model was subjected to intensive manual curation throughout the reconstruction stages to find out the metabolic specificities of this yeast. The final model includes 796 genes, 2465 reactions and 2127 metabolites, and its biomass equation is based on direct measurements of all major biomass components. The validation step was performed using experimental data obtained in this work, and simulation results evaluated the growth and lipid accumulation physiology of P. laurentii. Therefore, the papla-GEM will lead to a better understanding of the metabolic capabilities of P. laurentii and thus will be useful in systems metabolic engineering approaches.

Expression Profile of Selected Genes Involved in Storage Lipid Synthesis in a Model Oleaginous Yeast Species Yarrowia lipolytica.

Yarrowia lipolytica yeast is a model species of the group of oleaginous microorganisms capable of intracellular lipids accumulation in an amount exceeding 20% of the dry mass. Single cell oil biosynthesis can follow one of two biochemical pathways—de novo accumulation of cellular lipids in medium containing non-lipid carbon sources (including saccharides, glycerol) and ex novo microbial oil synthesis which involves fatty acids uptake from the environment. The mRNA expression of selected genes of de novo and ex novo lipid synthesis pathways was analyzed and correlated with the phenotypically observed features. It was proved that the accumulation yield of storage lipids via ex novo pathway was to some extent dependent on the limitation of the nitrogen source in the medium. It was also proposed that the synthesis of intracellular lipids in lipid-rich medium proceeded mainly via ex novo pathway, although the activity of genes encoding the enzymes of the de novo pathway were not completely inhibited at the stage of transcription by fatty acids present in the medium (e.g., ATP-citrate lyase). Molecular markers of two biosynthesis routes has been outlined and a hypothetical connection point between de novo and ex novo route were indicated.

Melanodevriesia, a New Genus of Endolichenic Oleaginous Black Yeast Recovered from the Inner Mongolia Region of China

Black yeasts are a phylogenetically diverse group of ascomycetous fungi that may exist in both unicellular and mycelial morphs. This group of fungi contains numerous commercially significant species as well as others whose precise roles are unknown, such as endolichenic species. There is currently a paucity of data about endolichenic black yeast species. To bridge this gap, we surveyed China's Inner Mongolia Autonomous Region in July 2019. Several fungal species associated with diverse lichens were isolated during this survey. Among these were two isolates of a previously unknown species of oleaginous black yeast fromMycosphaerellales. Analyses of morphological and molecular data revealed that these two isolates were closely related toXenodevriesia strelitziicola(Xenodevriesiaceae), although with significant differences. As a result, we established the genusMelanodevriesia gen. nov.to describe this previously unknown species,Melanodevriesia melanelixiae sp. nov.In addition, we used Transmission Electron Microscopy to visualise the intracellular oil bodies metabolised by this fungus in its unicellular state. The black yeast species identified in this study may have a wide range of commercial applications. More research is needed to determine the chemical composition of the microbial oil synthesized by this fungus and whether it has commercial value.