Subcellular engineering of lipase dependent pathways directed towards lipid related organelles for highly effectively compartmentalized biosynthesis of triacylglycerol derived products in Yarrowia lipolytica.

As an alternative to in vitro lipase dependent biotransformation and to traditional assembly of pathways in cytoplasm, the present study focused on targeting lipase dependent pathways to a subcellular compartment lipid body (LB), in combination with compartmentalization of associated pathways in other lipid relevant organelles including endoplasmic reticulum (ER) and peroxisome for efficient in vivo biosynthesis of fatty acid methyl esters (FAMEs) and hydrocarbons, in the context of improving Yarrowia lipolytica lipid pool. Through knock in and knock out of key genes involved in triacylglycerols (TAGs) biosynthesis and degradation, the TAGs content was increased to 51.5%, from 7.2% in parent strain. Targeting lipase dependent pathway to LB gave a 10-fold higher FAMEs titer (1028.0 mg/L) compared to cytosolic pathway (102.8 mg/L). Furthermore, simultaneously targeting lipase dependent pathway to LB, ER and peroxisome gave rise to the highest FAMEs titer (1644.8 mg/L). The subcellular compartment engineering strategy was extended to other lipase dependent pathways for fatty alkene and alkane biosynthesis, which resulted in a 14-fold titer enhancement compared to traditional cytosolic pathways. We developed yeast subcellular cell factories by directing lipase dependent pathways towards the TAGs storage organelle LB for efficient biosynthesis of TAG derived chemicals for the first time. The successful exploration of targeting metabolic pathways towards LB centered organelles is expected to promote subcellular compartment engineering for other lipid derived product biosynthesis.

Effect of Bulk MoS2 on the Metabolic Profile of Yeast.

MoS2, a kind of two-dimensional material with unique performances, has been widely used in many fields. However, an in-depth understanding of its toxicity is still needed, let alone its effects on the environmental microorganism. Herein, we used different methods, including metabolomics technology, to investigate the influence of bulk MoS2 (BMS) on yeast cells. The results indicated that high concentrations (1 mg/L and more) of BMS could destroy cell membrane and induce ROS accumulation. When exposed to a low concentration of BMS (0.1 mg/L), the intracellular concentrations of many metabolites (e.g., fumaric acid, lysine) increased. However, most of their concentrations descended significantly as the yeast cells were treated with BMS of high concentrations (1 mg/L and more). Metabolomics analysis further revealed that exposure to high concentrations of BMS could significantly affect some metabolic pathways such as amino acid and citrate cycle related metabolism. These findings will be beneficial for MoS2 toxicity assessment and further applications.

Laccase production from sucrose by recombinant Yarrowia lipolytica and its application to decolorization of environmental pollutant dyes.

Laccases are used in decolorization and biodegradation of synthetic dyes, bioremediation of industrial wastewaters and delignification of lignocellulosic compounds. The aims of the present study were the optimization of a recombinant laccase production in Yarrowia lipolytica yeast using sucrose as a main carbon source, and the application of the resulting enzyme to decolorization of synthetic dyes, which are problematic environmental pollutants. Taguchi's experimental design method was employed to optimize medium compounds. Recombinant laccase production by Y. lipolytica YL4 strain increased to 900 U L-1 after optimization of sucrose, ammonium chloride, yeast extract and thiamine levels in the modified PPB medium. Furthermore, the production rate reached 6760 U L-1 in a 5 L bioreactor which represents 4.5- and 33.5-fold increases compared to cultures that were in shake-flask with optimized and primary media, respectively. The supernatant containing secreted recombinant laccase was applied for decolorization of seven dyes. The effects of pH, the amount of enzyme and incubation period were verified. The effect of incubation time on dye decolorization by recombinant laccase was important, which has an influence of greater extent than 90% after 48 h for all dyes. The Trametes versicolor laccase can be efficiently produced in Y. lipolytica and the recombinant enzyme has a considerable potential in the decolorization of pollutant synthetic dyes.

In silico and in vivo analysis of signal peptides effect on recombinant glucose oxidase production in nonconventional yeast Yarrowia lipolytica.

Signal peptide (SP) is an important factor and biobrick in the production and secretion of recombinant proteins. The aim of this study was in silico and in vivo analysis of SPs effect on the production of recombinant glucose oxidase (GOX) in Yarrowia lipolytica. Several in silico softwares, namely SignalP4, Signal-CF, Phobius, WolfPsort 0.2, SOLpro and ProtParam, were used to analyse the potential of 15 endogenous and exogenous SPs for the secretion of recombinant GOX in Y. lipolytica. According to in silico results, the SP of GOX was predicted as suitable in terms of high secretory potential and of protein solubility and stability which is chosen for in vivo analysis. The recombinant Y. lipolytica strain produced 280 U/L of extracellular GOX after 7 days in YPD medium. The results show that the SP of GOX can be applied to efficient production of extracellular heterologous proteins and metabolic engineering in Y. lipolytica.

Harnessing biodiesel-producing microbes: from genetic engineering of lipase to metabolic engineering of fatty acid biosynthetic pathway.

Microbial production routes, notably whole-cell lipase-mediated biotransformation and fatty-acids-derived biosynthesis, offer new opportunities for synthesizing biodiesel. They compare favorably to immobilized lipase and chemically catalyzed processes. Genetically modified whole-cell lipase-mediated in vitro route, together with in vivo and ex vivo microbial biosynthesis routes, constitutes emerging and rapidly developing research areas for effective production of biodiesel. This review presents recent advances in customizing microorganisms for producing biodiesel, via genetic engineering of lipases and metabolic engineering (including system regulation) of fatty-acids-derived pathways. Microbial hosts used include Escherichia coli, Saccharomyces cerevisiae, Pichia pastoris and Aspergillus oryzae. These microbial cells can be genetically modified to produce lipases under different forms: intracellularly expressed, secreted or surface-displayed. They can be metabolically redesigned and systematically regulated to obtain balanced biodiesel-producing cells, as highlighted in this study. Such genetically or metabolically modified microbial cells can support not only in vitro biotransformation of various common oil feedstocks to biodiesel, but also de novo biosynthesis of biodiesel from glucose, glycerol or even cellulosic biomass. We believe that the genetically tractable oleaginous yeast Yarrowia lipolytica could be developed to an effective biodiesel-producing microbial cell factory. For this purpose, we propose several engineered pathways, based on lipase and wax ester synthase, in this promising oleaginous host.

Mutagenesis of conserved active site residues of dihydrolipoamide succinyltransferase enhances the accumulation of α-ketoglutarate in Yarrowia lipolytica.

α-Ketoglutarate (α-KG) is an important intermediate in the tricarboxylic acid cycle and has broad applications. The mitochondrial ketoglutarate dehydrogenase (KGDH) complex catalyzes the oxidation of α-KG to succinyl-CoA. Disruption of KGDH, which may enhance the accumulation of α-KG theoretically, was found to be lethal to obligate aerobic cells. In this study, individual overexpression of dihydrolipoamide succinyltransferase (DLST), which serves as the inner core of KGDH, decreased overall activity of the enzyme complex. Furthermore, two conserved active site residues of DLST, His419, and Asp423 were identified. In order to determine whether these residues are engaged in enzyme reaction or not, these two conserved residues were individually mutated. Analysis of the kinetic parameters of the enzyme variants provided evidence that the catalytic reaction of DLST depended on residues His419 and Asp423. Overexpression of mutated DLST not only impaired balanced assembly of KGDH, but also disrupted the catalytic integrity of the enzyme complex. Replacement of the Asp423 residue by glutamate increased extracellular α-KG by 40 % to 50 g L(-1) in mutant strain. These observations uncovered catalytic roles of two conserved active site residues of DLST and provided clues for effective metabolic strategies for rational carbon flux control for the enhanced production of α-KG and related bioproducts.

Applying pathway engineering to enhance production of alpha-ketoglutarate in Yarrowia lipolytica.

α-Ketoglutarate (α-KG), one of short-chain carboxylates of high commercial relevance, has been widely used in food, medicine, chemical, and cosmetic fields. Compared to other carboxylates, α-KG occupies key positions in the tricarboxylate cycle (TCA cycle) and amino acid metabolic pathway, the over-accumulation of α-KG is restricted both by tighter carbon and nitrogen regulation process. Biotechnology production of α-KG on large industrial level has been impeded by many obstacles. This review aims at highlighting and stating recent efforts toward improving the yield and titer of α-KG in the strains of Yarrowia lipolytica to reach industrial relevance. Fermentation process optimization concerning feedstock utilization, dissolved oxygen controlling, pH manipulation and establishment of fed-batch process, have been assessed and evaluated. Moreover, pathway engineering routes have been applied for enhancing carbon commitment to α-KG, blocking competing pathways, regenerating of co-factors and regulating of carboxylate transporters to facilitate production and accumulation of α-KG. Although no engineered strain can satisfy the requirements of industrial production relevance to date, these strategies provide many clues for accelerating strain development for α-KG production.

Overproduction of pro-transglutaminase from Streptomyces hygroscopicus in Yarrowia lipolytica and its biochemical characterization.

BACKGROUND: Transglutaminases (TGase), synthesized as a zymogen (pro-TGase) in Streptomyces sp., are important enzymes in food industry. Due to the important applications of TGase in food industry, obtaining robust and food-safe TGase-producing strains has attracted much attention during the past decade. In this study, Streptomyces hygroscopicus pro-TGase was efficiently expressed and secreted by a food-grade host, Yarrowia lipolytica, without antibiotic markers. RESULTS: The pro-TGase gene was cloned into integrative vectors pINA1296 (monocopy) and pINA1297 (multicopy), and was used to transform the Y. lipolytica Po1g or Po1h strain, respectively. Expression was driven by a recombinant hp4d promoter and secretion obtained using a XPR2 pre-sequence as a signal peptide. The highest yield of extracellular pro-TGase produced by the recombinant Po1h strain corresponded to 5.3 U/mL of TGase, a level 8.8 fold higher than that obtained using the recombinant Po1g strain. Asparagines in two potential Asn-linked glycosylation sites (Asn160 and Asn355) from pro-TGase were mutated to glutamine individually or simultaneously, yielding the deglycosylated variants N160Q, N355Q, and N160Q/N355Q. The activities of N160Q, N355Q and N160Q/N355Q constructs were respectively 5.3 U/mL, 7.8 U/mL, and 3.0 U/mL, equivalent to 100 %, 147 %, and 57 % of that from wild-type pro-TGase. The TGase yield of N355Q variant was raised to 35.3 U/mL of by using a glycerol feeding strategy in a 3 L fermenter. The optimal pH and temperature of the activated pro-TGase, and of its deglycosylated variants, were in the range of 5.0-6.0 pH and 40-45 °C, respectively. The half-life of the recombinant wild-type pro-TGase at 37 °C reached 34.0 min, and those of the variants were from 24.2 min to 11.5 min. In contrast to the wild-type pro-TGase, all of the variants had decreased specific activities, and both the K m and k cat values of the variants decreased accordingly. CONCLUSIONS: This study constitutes the first report of the heterologous expression of a pro-TGase in Y. lipolytica, and provides new possibilities for the efficient production of TGases used in food processing.

Yarrowia lipolytica: recent achievements in heterologous protein expression and pathway engineering.

The oleaginous yeast Yarrowia lipolytica has become a recognized system for expression/secretion of heterologous proteins. This non-conventional yeast is currently being developed as a workhorse for biotechnology by several research groups throughout the world, especially for single-cell oil production, whole cell bioconversion and upgrading of industrial wastes. This mini-review presents established tools for protein expression in Y. lipolytica and highlights novel developments in the areas of promoter design, surface display, and host strain or metabolic pathway engineering. An overview of the industrial and commercial biotechnological applications of Y. lipolytica is also presented.

Exploring medium-chain-length polyhydroxyalkanoates production in the engineered yeast Yarrowia lipolytica.

Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) are a large class of biopolymers that have attracted extensive attention as renewable and biodegradable bio-plastics. They are naturally synthesized via fatty acid de novo biosynthesis pathway or ß-oxidation pathway from Pseudomonads. The unconventional yeast Yarrowia lipolytica has excellent lipid/fatty acid catabolism and anabolism capacity depending of the mode of culture. Nevertheless, it cannot naturally synthesize PHA, as it does not express an intrinsic PHA synthase. Here, we constructed a genetically modified strain of Y. lipolytica by heterologously expressing PhaC1 gene from P. aeruginosa PAO1 with a PTS1 peroxisomal signal. When in single copy, the codon optimized PhaC1 allowed the synthesis of 0.205 % DCW of PHA after 72 h cultivation in YNBD medium containing 0.1 % oleic acid. By using a multi-copy integration strategy, PHA content increased to 2.84 % DCW when the concentration of oleic acid in YNBD was 1.0 %. Furthermore, when the recombinant yeast was grown in the medium containing triolein, PHA accumulated up to 5.0 % DCW with as high as 21.9 g/L DCW, which represented 1.11 g/L in the culture. Our results demonstrated the potential use of Y. lipolytica as a promising microbial cell factory for PHA production using food waste, which contains lipids and other essential nutrients.

Effects of pyruvate dehydrogenase subunits overexpression on the α-ketoglutarate production in Yarrowia lipolytica WSH-Z06.

Yarrowia lipolytica WSH-Z06 harbours a promising capability to oversynthesize α-ketoglutarate (α-KG). Its wide utilization is hampered by the formation of high concentrations of pyruvate. In this study, a metabolic strategy for the overexpression of the α and ß subunits of pyruvate dehydrogenase E1, E2 and E3 components was designed to reduce the accumulation of pyruvate. Elevated expression level of α subunit of E1 component improved the α-KG production and reduced the pyruvate accumulation. Due to a reduction in the acetyl-CoA supply, neither the growth of cells nor the synthesis of α-KG was restrained by the overexpression of ß subunit of E1, E2 and E3 components. Furthermore, via the overexpression of these thiamine pyrophosphate (TPP)-binding subunits, the dependency of pyruvate dehydrogenase on thiamine was diminished in strains T1 and T2, in which α and ß subunits of E1 component were separately overexpressed. In these two recombinant strains, the accumulation of pyruvate was insensitive to variations in exogenous thiamine. The results suggest that α-KG production can be enhanced by altering the dependence on TPP of pyruvate dehydrogenase and that the competition for the cofactor can be switched to ketoglutarate dehydrogenase via separate overexpression of the TPP-binding subunits of pyruvate dehydrogenase. The results presented here provided new clue to improve α-KG production.

Engineering Yarrowia lipolytica as a Cellulolytic Cell Factory for Production of p-Coumaric Acid from Cellulose and Hemicellulose.

De novo biosynthesis of high-value added food additive p-coumaric acid (p-CA) direct from cellulose/hemicellulose is a more sustainable route compared to the chemical route, considering the abundant cellulose/hemicellulose resources. In this study, a novel factory was constructed for the production of p-CA in Yarrowia lipolytica using cellulose/hemicellulose as the sole carbon source. Based on multicopy integration of the TAL gene and reprogramming the shikimic acid pathway, the engineered strain produced 1035.5 ± 67.8 mg/L p-CA using glucose as a carbon source. The strains with overexpression of cellulases and hemicellulases produced 84.3 ± 2.4 and 65.3 ± 4.6 mg/L p-CA, using cellulose (carboxymethyl-cellulose) or hemicellulose (xylan from bagasse) as the carbon source, respectively. This research demonstrated the feasibility of conversion of cost-effective cellulose/hemicellulose into a value-added product and provided a sustainable cellulolytic cell factory for the utilization of cellulose/hemicellulose.

Concerted electron/proton transfer mechanism in the oxidation of phenols by laccase.

This study aimed to assess structural requirements in the enzyme/substrate interactions that are responsible for tuning the enzymatic reactivity. To better assess the role of the aspartic residue in the substrate-binding pocket of basidiomycete-type laccases, we compared the catalytic efficiency of wild-type enzymes to that of a mutant in which carboxylic acid residue Asp206 was changed to alanine. Oxidation efficiency towards phenolic substrates by laccases of Trametes villosa, Trametes versicolor and a T. versicolor D206A mutant was studied at two pH values. By the Hammett approach and Marcus analysis, we obtained unambiguous evidence that the oxidation takes place by a concerted electron/proton transfer (EPT) mechanism, and that at pH 5 (optimum pH for enzyme activity) the phenolic proton is transferred to Asp206 during the concerted electron/proton transfer process.

Tunable nano-oleosomes derived from engineered Yarrowia lipolytica.

Oleosomes are discrete organelles filled with neutral lipids surrounded by a protein-embedded phospholipid monolayer. Their simple yet robust structure, as well as their amenability to biological, chemical, and physical processing, can be exploited for various biotechnology applications. In this study, we report facile biosynthesis of functionalized oleosomes within oleaginous yeast Yarrowia lipolytica, through expression of oleosin fusion proteins. By fusing a cDNA clone of a sesame oleosin with either the coding sequence of a red fluorescent protein mCherry or a cellulosomal scaffolding protein cohesin from Clostridium cellulolyticum, these oleosin-fusion proteins were efficiently expressed and specifically targeted to and anchored on the surface of the oleosomes within the Y. lipolytica cells. The engineered oleosomes can be easily separated from the Y. lipolytica cell extract via floating centrifugation and both mCherry and cohesin domains are shown to be functional. Upon sonication, the engineered Yarrowia oleosomes exhibit a mean diameter of 200-300 nm and are found to be highly stable. The feasibility of co-displaying multiple proteins on the Yarrowia oleosomes was demonstrated by incubating cohesin-displaying oleosomes with different dockerin-fusion proteins. Based on this strategy, engineered oleosomes with both cell-targeting and reporting activities were created and shown to be functional. Taken together, the Yarrowia oleosome surface display system in which oleosin serves as an efficient membrane anchor motif shows great promise as a simple platform for creating tunable nanoparticles.

Study of the persistence and dynamics of recombinant mCherry-producing Yarrowia lipolytica strains in the mouse intestine using fluorescence imaging.

Yarrowia lipolytica is a dimorphic oleaginous non-conventional yeast widely used as a powerful host for expressing heterologous proteins, as well as a promising source of engineered cell factories for various applications. This microorganism has a documented use in Feed and Food and a GRAS (generally recognized as safe) status. Moreover, in vivo studies demonstrated a beneficial effect of this yeast on animal health. However, despite the focus on Y. lipolytica for the industrial manufacturing of heterologous proteins and for probiotic effects, its potential for oral delivery of recombinant therapeutic proteins has seldom been evaluated in mammals. As the first steps towards this aim, we engineered two Y. lipolytica strains, a dairy strain and a laboratory strain, to produce the model fluorescent protein mCherry. We demonstrated that both Y. lipolytica strains transiently persisted for at least 1 week after four daily oral administrations and they maintained the active expression of mCherry in the mouse intestine. We used confocal microscopy to image individual Y. lipolytica cells of freshly collected intestinal tissues. They were found essentially in the lumen and they were rarely in contact with epithelial cells while transiting through the ileum, caecum and colon of mice. Taken as a whole, our results have shown that fluorescent Y. lipolytica strains constitute novel tools to study the persistence and dynamics of orally administered yeasts which could be used in the future as oral delivery vectors for the secretion of active therapeutic proteins in the gut.

Enhanced alpha-ketoglutaric acid production in Yarrowia lipolytica WSH-Z06 by regulation of the pyruvate carboxylation pathway.

In previous research, a thiamine-auxotrophic yeast for alpha-ketoglutaric acid (KGA) overproduction was screened in our laboratory and named Yarrowia lipolytica WSH-Z06 (CCTCC no. M207143). However, the high concentration of by-products (mainly pyruvate) limited its application on an industrial scale. To enhance KGA production and reduce pyruvate (PA) accumulation, the pyruvate carboxylation pathway was regulated. By overexpressing the pyruvate carboxylase genes ScPYC1 from Saccharomyces cerevisiae and RoPYC2 from Rhizopus oryzae in Y. lipolytica WSH-Z06, the yields of KGA in Y. lipolytica-ScPYC1 and Y. lipolytica-RoPYC2 increased by 24.5 and 35.3 %, and the yields of PA decreased by 51.9 and 69.8 % in shake flasks, respectively. These changes in the expression levels and activities of key intracellular enzymes showed that enhancing the pyruvate carboxylation pathway had successfully redistributed the carbon flux from PA to KGA. Finally, by controlling the pH in a 3-L fermenter, the maximum concentration of KGA in Y. lipolytica-RoPYC2 reached 62.5 g L⁻¹ with an evident decrease in PA yield from 35.2 to 13.5 g L⁻¹.

How is the reactivity of laccase affected by single-point mutations? Engineering laccase for improved activity towards sterically demanding substrates.

In spite of its broad specificity among phenols, Trametes versicolor laccase hardly succeeds in oxidizing hindered substrates. To improve the oxidation ability of this laccase towards bulky phenolic substrates, we designed a series of single-point mutants on the basis of the amino-acid layout inside the reducing substrate active site known from the crystal structure of the enzyme. Site-directed mutagenesis has addressed four phenylalanine residues in key positions 162, 265, 332, and 337 at the entrance of the binding pocket, as these residues appeared instrumental for docking of the substrate. These phenylalanines were replaced by smaller-sized but still apolar alanines. A double mutant F162A/F332A was also designed. Measurement of the oxidation efficiency towards encumbered phenols has shown that mutant F162A was more efficient than the wild-type laccase. The double mutant F162A/F332A led to 98% consumption of bisphenol A in only 5 h and was more efficient than the single mutants in the aerobic oxidation of this bulky substrate. In contrast, lack of appropriate hydrophobic interactions with the substrate possibly depresses the oxidation outcome with mutants F265A and F332A. One explanation for the lack of reactivity of mutant F337A, supported by literature reports, is that this residue is part of the second coordination shell of T1 Cu. A mutation at this position thus leads to a drastic coordination shell destabilization. Thermal stability of the mutants and their resistance in a mixed water-dioxane solvent have also been investigated.

Yarrowia lipolytica Strains and Their Biotechnological Applications: How Natural Biodiversity and Metabolic Engineering Could Contribute to Cell Factories Improvement.

Among non-conventional yeasts of industrial interest, the dimorphic oleaginous yeast Yarrowia lipolytica appears as one of the most attractive for a large range of white biotechnology applications, from heterologous proteins secretion to cell factories process development. The past, present and potential applications of wild-type, traditionally improved or genetically modified Yarrowia lipolytica strains will be resumed, together with the wide array of molecular tools now available to genetically engineer and metabolically remodel this yeast. The present review will also provide a detailed description of Yarrowia lipolytica strains and highlight the natural biodiversity of this yeast, a subject little touched upon in most previous reviews. This work intends to fill this gap by retracing the genealogy of the main Yarrowia lipolytica strains of industrial interest, by illustrating the search for new genetic backgrounds and by providing data about the main publicly available strains in yeast collections worldwide. At last, it will focus on exemplifying how advances in engineering tools can leverage a better biotechnological exploitation of the natural biodiversity of Yarrowia lipolytica and of other yeasts from the Yarrowia clade.

Inulin hydrolysis and citric acid production from inulin using the surface-engineered Yarrowia lipolytica displaying inulinase.

The INU1 gene encoding exo-inulinase cloned from Kluyveromyces marxianus CBS 6556 was ligated into the surface display plasmid and expressed in the cells of the marine-derived yeast Yarrowia lipolytica which can produce citric acid. The expressed inulinase was immobilized on the yeast cells. The activity of the immobilized inulinase with 6 x His tag was found to be 22.6 U mg(-1) of cell dry weight after cell growth for 96 h. The optimal pH and temperature of the displayed inulinase were 4.5 and 50 degrees C, respectively and the inulinase was stable in the pH range of 3-8 and in the temperature range of 0-50 degrees C. During the inulin hydrolysis, the optimal inulin concentration was 12.0% and the optimal amount of added inulinase was 181.6 U g(-1) of inulin. Under such conditions, over 77.9% of inulin was hydrolyzed within 10h and the hydrolysate contained main monosaccharides and disaccharides, and minor trisaccharides. During the citric acid production in the flask level, the recombinant yeast could produce 77.9 g L(-1) citric acid and 5.3 g L(-1) iso-citric acid from inulin while 68.9 g L(-1) of citric acid and 4.1 g L(-1) iso-citric acid in the fermented medium were attained within 312 h of the 2-L fermentation, respectively.

Expression of inulinase gene in the oleaginous yeast Yarrowia lipolytica and single cell oil production from inulin-containing materials.

Yarrowia lipolytica ACA-DC 50109 has been reported to be an oleaginous yeast and significant quantities of lipids were accumulated inside the yeast cells. In this study, the INU1 gene encoding exo-inulinase cloned from Kluyveromyces marxianus CBS 6556 was ligated into the expression plasmid pINA1317 and expressed in the cells of the oleaginous yeast. The activity of the inulinase with 6 × His tag secreted by the transformant Z31 obtained was found to be 41.7U mL(-1) after cell growth for 78 h. After optimization of the medium and cultivation conditions for single cell oil production, the transformant could accumulate 46.3% (w/w) oil from inulin in its cells and cell dry weight was 11.6 g L(-1) within 78 h at the flask level. During the 2-L fermentation, the transformant could accumulate 48.3% (w/w) oil from inulin in its cells and cell dry weight was 13.3 g L(-1) within 78 h while the transformant could accumulate 50.6% (w/w) oil from extract of Jerusalem artichoke tubers in its cells and cell dry weight was 14.6 g L(-1) within 78 h. At the end of fermentation, most of the added sugar was utilized by the transformant cells. Over 91.5% of the fatty acids from the transformant cultivated in the extract of Jerusalem artichoke tubercles was C(16:0), C(18:1) and C(18:2), especially C(18:1) (58.5%).