Metabolic engineering of Saccharomyces cerevisiae for production of fatty acid short- and branched-chain alkyl esters biodiesel

Saccharomyces cerevisiae cellular engineering for the production of FAME biodiesel

The unsustainable and widespread utilization of fossil fuels continues to drive the rapid depletion of global supplies. Biodiesel has emerged as one of the most promising alternatives to conventional diesel, leading to growing research interest in its production. Microbes can facilitate the de novo synthesis of a type of biodiesel in the form of fatty acid methyl esters (FAMEs). In this study, Saccharomyces cerevisiae metabolic activity was engineered to facilitate enhanced FAME production. Initially, free fatty acid concentrations were increased by deleting two acetyl-CoA synthetase genes (FAA1, FAA4) and an acyl-CoA oxidase gene (POX1). Intracellular S-adenosylmethionine (SAM) levels were then enhanced via the deletion of an adenosine kinase gene (ADO1) and the overexpression of a SAM synthetase gene (SAM2). Lastly, the S. cerevisiae strain overproducing free fatty acids and SAM were manipulated to express a plasmid encoding the Drosophila melanogaster Juvenile Hormone Acid O-Methyltransferase (DmJHAMT). Using this combination of engineering approaches, a FAME concentration of 5.79 ± 0.56 mg/L was achieved using these cells in the context of shaking flask fermentation. To the best of our knowledge, this is the first detailed study of FAME production in S. cerevisiae. These results will provide a valuable basis for future efforts to engineer S. cerevisiae strains for highly efficient production of biodiesel.

Wax Ester and Triacylglycerol Production in Acinetobacter baumannii: Role in Osmostress Protection, Reactive Oxygen Species, and Antibiotic Sensitivity

Wax esters (WEs) are neutral lipids that are produced by many different bacteria as potential carbon and energy storage compounds. Comparatively little is known about the role of WE in pathogenic bacteria. The opportunistic pathogen Acinetobacter baumannii is a major cause of hospital-acquired infections worldwide. Salt and desiccation resistance foster A. baumannii infections such as urinary tract infections and allow for reinfection when bacteria are taken up from dry surfaces in the hospital environment. Here we report on WE and triacylglycerol (TAG) production in A. baumannii as a response to nitrogen limitation and high salt stress. Fatty acids and fatty alcohols with chain lengths of C16 and C18 were identified as the most prominent WE constituents. We identified the terminal key enzyme of WE biosynthesis, the bifunctional wax ester synthase/acylCoA:diacylglycerol acyltransferase (WS/DGAT) encoded by the wax/dgat gene, and demonstrated that transcription of wax/dgat and production of WS/DGAT are independent of the nitrogen concentration. A Δwax/dgat mutant was impaired in growth in the presence of high salt concentration and was more sensitive to imipenem and reactive oxygen species.

Directed evolution of a wax ester synthase for production of fatty acid ethyl esters in Saccharomyces cerevisiae

Wax ester synthases (WSs) utilize a fatty alcohol and a fatty acyl-coenzyme A (activated fatty acid) to synthesize the corresponding wax ester. There is much interest in developing novel cell factories that can produce shorter esters, e.g., fatty acid ethyl esters (FAEEs), with properties similar to biodiesel in order to use these as transportation fuels. However, ethanol is a poor substrate for WSs, and this may limit the biosynthesis of FAEEs. Here, we implemented a random mutagenesis approach to enhance the catalytic efficiency of a WS from Marinobacter hydrocarbonoclasticus (MhWS2, encoded by the ws2 gene). Our selection system was based on FAEE formation serving as a detoxification mechanism for excessive oleate, where high WS activity was essential for a storage-lipid free yeast to survive. A random mutagenesis library of ws2 was used to transform the storage-lipid free yeast, and mutants could be selected by plating the transformants on oleate containing plates. The variants encoding WS with improved activity were sequenced, and an identified point mutation translated into the residue substitution at position A344 was discovered to substantially increase the selectivity of MhWS2 toward ethanol and other shorter alcohols. Structural modeling indicated that an A344T substitution might affect the alcohol selectivity due to change of both steric effects and polarity changes near the active site. This work not only provides a new WS variant with altered selectivity to shorter alcohols but also presents a new high-throughput selection system to isolate WSs with a desired selectivity. KEY POINTS: • The work provides WS variants with altered substrate preference for shorter alcohols • A novel method was developed for directed evolution of WS of desired selectivity.

Mutualistic microbial community of Bacillus amyloliquefaciens and recombinant Yarrowia lipolytica co-produced lipopeptides and fatty acids from food waste

Bioconversion is an important method for transforming food waste (FW) into high value-added products, rendering it harmless, and recycling resources. An artificial microbial consortium (AMC) was constructed to produce FW-based lipopeptides in order to investigate the strategy of FW bioconversion into value-added products. Exogenous fatty acids as a precursor significantly improved the lipopeptide production of Bacillus amyloliquefaciens HM618. To enhance fatty acid synthesis and efflux in AMC, the recombinant Yarrowia lipolytica YL21 (strain YL21) was constructed by screening 12 target genes related to fatty acids to replace exogenous fatty acids in order to improve lipopeptide production. The levels of fengycin, surfactin, and iturin A in the AMC of strains HM618 and YL21 reached 76.19, 192.80, and 31.32 mg L^-1, increasing 7.24-, 12.13-, and 3.23-fold compared to the results from the pure culture of strain HM618 in flask with Landy medium, respectively. Furthermore, free fatty acids were almost undetectable in the co-culture of strains HM618 and YL21, although its level was around 1.25 g L^-1 in the pure culture of strain YL21 with Landy medium. Interestingly, 470.24 mg L^-1 of lipopeptides and 18.11 g L^-1 of fatty acids were co-produced in this AMC in a bioreactor with FW medium. To our knowledge, it is the first report of FW biotransformation into co-produce of lipopeptides and fatty acids in the AMC of B. amyloliquefaciens and Y. lipolytica. These results provide new insights into the biotransformation potential of FW for value-added co-products by AMC.

Biodiesel Produced from Propanol and Longer Chain Alcohols—Synthesis and Properties

Biodiesel has established itself as a renewable fuel that is used in transportation worldwide and is partially or in some cases completely replacing conventional fuels. Chemically, biodiesel is a fatty acid monoalkyl ester (FAAE). Generally, the term biodiesel refers to the fatty acid methyl or ethyl esters (FAME or FAEE). Herein, an overview of the research on the synthesis of FAAE in which the alkyl moiety is a C3+ alkyl chain (branched/unbranched) is given. In addition, a comparison of the properties of the aforementioned FAAE with each other, with FAME and FAEE, and with fuel standards is given. The length of the alkyl chain has a major influence on viscosity, while pour point temperatures are generally lower when branched alcohols are used, but the fatty acid part of the molecule also has a major influence. The development of new pathways for the synthesis of higher alcohols from biomass opens a future perspective for the production of long chain FAAE as biofuels, fuel additives, or biolubricants. Due to their properties, FAAEs produced from C3–C5 alcohols have the potential to be used as fuels, while all C3+ FAAEs can be used as valuable bioadditives, and C8+ FAAEs can be used as biolubricants and viscosity improvers.

Transporter-Driven Engineering of a Genetic Biosensor for the Detection and Production of Short-Branched Chain Fatty Acids in Saccharomyces cerevisiae

Biosensors can be used for real-time monitoring of metabolites and high-throughput screening of producer strains. Use of biosensors has facilitated strain engineering to efficiently produce value-added compounds. Following our recent work on the production of short branched-chain fatty acids (SBCFAs) in engineered Saccharomyces cerevisiae, here we harnessed a weak organic acid transporter Pdr12p, engineered a whole-cell biosensor to detect exogenous and intracellular SBCFAs and optimized the biosensor’s performance by varying PDR12 expression. We firstly constructed the biosensor and evaluated its response to a range of short-chain carboxylic acids. Next, we optimized its sensitivity and operational range by deletion and overexpression of PDR12. We found that the biosensor responded to exogenous SBCFAs including isovaleric acid, isobutyric acid and 2-methylbutanoic acid. PDR12 deletion enhanced the biosensor’s sensitivity to isovaleric acid at a low concentration and PDR12 overexpression shifted the operational range towards a higher concentration. Lastly, the deletion of PDR12 improved the biosensor’s sensitivity to the SBCFAs produced in our previously engineered SBCFA-overproducing strain. To our knowledge, our work represents the first study on employing an ATP-binding-cassette transporter to engineer a transcription-factor-based genetic biosensor for sensing SBCFAs in S. cerevisiae. Our findings provide useful insights into SBCFA detection by a genetic biosensor that will facilitate the screening of SBCFA-overproducing strains.

Bioengineered microbial platforms for biomass-derived biofuel production - A review

Global warming issues, rapid fossil fuel diminution, and increasing worldwide energy demands have diverted accelerated attention in finding alternate sources of biofuels and energy to combat the energy crisis. Bioconversion of lignocellulosic biomass has emerged as a prodigious way to produce various renewable biofuels such as biodiesel, bioethanol, biogas, and biohydrogen. Ideal microbial hosts for biofuel synthesis should be capable of using high substrate quantity, tolerance to inhibiting substances and end-products, fast sugar transportation, and amplified metabolic fluxes to yielding enhanced fermentative bioproduct. Genetic manipulation and microbes' metabolic engineering are fascinating strategies for the economical production of next-generation biofuel from lignocellulosic feedstocks. Metabolic engineering is a rapidly developing approach to construct robust biofuel-producing microbial hosts and an important component for future bioeconomy. This approach has been widely adopted in the last decade for redirecting and revamping the biosynthetic pathways to obtain a high titer of target products. Biotechnologists and metabolic scientists have produced a wide variety of new products with industrial relevance through metabolic pathway engineering or optimizing native metabolic pathways. This review focuses on exploiting metabolically engineered microbes as promising cell factories for the enhanced production of advanced biofuels.

The Studies in Constructing Yeast Cell Factories for the Production of Fatty Acid Alkyl Esters

Fatty acid alkyl esters have broad applications in biofuels, lubricant formulas, paints, coatings, and cosmetics. Traditionally, these esters are mostly produced through unsustainable and energy-intensive processes. In contrast, microbial production of esters from renewable and sustainable feedstocks may provide a promising alternative and has attracted widespread attention in recent years. At present, yeasts are used as ideal hosts for producing such esters, due to their availability for high-density fermentation, resistance to phage infection, and tolerance against toxic inhibitors. Here, we summarize recent development on the biosynthesis of alkyl esters, including fatty acid ethyl esters (FAEEs), fatty acid short-branched chain alkyl esters (FASBEs), and wax esters (WEs) by various yeast cell factories. We focus mainly on the enzyme engineering strategies of critical wax ester synthases, and the pathway engineering strategies employed for the biosynthesis of various ester products. The bottlenecks that limit productivity and their potential solutions are also discussed in this review.

¡Viva la mitochondria!: harnessing yeast mitochondria for chemical production

The mitochondria, often referred to as the powerhouse of the cell, offer a unique physicochemical environment enriched with a distinct set of enzymes, metabolites and cofactors ready to be exploited for metabolic engineering. In this review, we discuss how the mitochondrion has been engineered in the traditional sense of metabolic engineering or completely bypassed for chemical production. We then describe the more recent approach of harnessing the mitochondria to compartmentalize engineered metabolic pathways, including for the production of alcohols, terpenoids, sterols, organic acids and other valuable products. We explain the different mechanisms by which mitochondrial compartmentalization benefits engineered metabolic pathways to boost chemical production. Finally, we discuss the key challenges that need to be overcome to expand the applicability of mitochondrial engineering and reach the full potential of this emerging field.

Analytical methods in fatty acid analysis for microbial applications: the recent trends

Fatty acids are among the most important components of many biological systems and have been highlighted in many research fields in recent decades. In the food industry, it is important to check the amount and types of fatty acids in edible oils, beverages and other foods products, and checking the fatty acids parameters are among the quality control parameters for those products. In medical applications, investigation of fatty acids in biological samples and comparing imbalances in them can help to diagnose some diseases. On the other hand, the development of cell factories for the production of biofuels and other valuable chemicals requires the accurate analysis of fatty acids, which serve as precursors in development of those products. As a result, given all these different applications of fatty acids, rapid and accurate methods for characterization and quantification of fatty acids are essential. In recent years, various methods for the analysis of fatty acids have been proposed, which according to the specific purpose of the analysis, some of them can be used with consideration of speed, accuracy and cost. In this article, the available methods for the analysis of fatty acids are reviewed with a special emphasis on the analysis of microbial samples to pave the way for more widespread metabolic engineering research.

Opportunities and Challenges for Microbial Synthesis of Fatty Acid-Derived Chemicals (FACs)

Global warming and uneven distribution of fossil fuels worldwide concerns have spurred the development of alternative, renewable, sustainable, and environmentally friendly resources. From an engineering perspective, biosynthesis of fatty acid-derived chemicals (FACs) is an attractive and promising solution to produce chemicals from abundant renewable feedstocks and carbon dioxide in microbial chassis. However, several factors limit the viability of this process. This review first summarizes the types of FACs and their widely applications. Next, we take a deep look into the microbial platform to produce FACs, give an outlook for the platform development. Then we discuss the bottlenecks in metabolic pathways and supply possible solutions correspondingly. Finally, we highlight the most recent advances in the fast-growing model-based strain design for FACs biosynthesis.

Engineering an Alcohol-Forming Fatty Acyl-CoA Reductase for Aldehyde and Hydrocarbon Biosynthesis in Saccharomyces cerevisiae

Aldehydes are a class of highly versatile chemicals that can undergo a wide range of chemical reactions and are in high demand as starting materials for chemical manufacturing. Biologically, fatty aldehydes can be produced from fatty acyl-CoA by the action of fatty acyl-CoA reductases. The aldehydes produced can be further converted enzymatically to other valuable derivatives. Thus, metabolic engineering of microorganisms for biosynthesizing aldehydes and their derivatives could provide an economical and sustainable platform for key aldehyde precursor production and subsequent conversion to various value-added chemicals. Saccharomyces cerevisiae is an excellent host for this purpose because it is a robust organism that has been used extensively for industrial biochemical production. However, fatty acyl-CoA-dependent aldehyde-forming enzymes expressed in S. cerevisiae thus far have extremely low activities, hence limiting direct utilization of fatty acyl-CoA as substrate for aldehyde biosynthesis. Toward overcoming this challenge, we successfully engineered an alcohol-forming fatty acyl-CoA reductase for aldehyde production through rational design. We further improved aldehyde production through strain engineering by deleting competing pathways and increasing substrate availability. Subsequently, we demonstrated alkane and alkene production as one of the many possible applications of the aldehyde-producing strain. Overall, by protein engineering of a fatty acyl-CoA reductase to alter its activity and metabolic engineering of S. cerevisiae, we generated strains with the highest reported cytosolic aliphatic aldehyde and alkane/alkene production to date in S. cerevisiae from fatty acyl-CoA.

Sustainable production of FAEE biodiesel using the oleaginous yeast Yarrowia lipolytica

Fatty acid ethyl esters (FAEEs) are fatty acid‐derived molecules and serve as an important form of biodiesel. The oleaginous yeast Yarrowia lipolytica is considered an ideal host platform for the production of fatty acid‐derived products due to its excellent lipid accumulation capacity. In this proof‐of‐principle study, several metabolic engineering strategies were applied for the overproduction of FAEE biodiesel in Y. lipolytica. Here, chromosome‐based co‐overexpression of two heterologous genes, namely, PDC1 (encoding pyruvate decarboxylase) and ADH1 (encoding alcohol dehydrogenase) from Saccharomyces cerevisiae, and the endogenous GAPDH (encoding glyceraldehyde‐3‐phosphate dehydrogenase) gene of Y. lipolytica resulted in successful biosynthesis of ethanol at 70.8 mg/L in Y. lipolytica. The engineered Y. lipolytica strain expressing the ethanol synthetic pathway together with a heterologous wax ester synthase (MhWS) exhibited the highest FAEE titer of 360.8 mg/L, which is 3.8‐fold higher than that of the control strain when 2% exogenous ethanol was added to the culture medium of Y. lipolytica. Furthermore, a synthetic microbial consortium comprising an engineered Y. lipolytica strain that heterologously expressed MhWS and a S. cerevisiae strain that could provide ethanol as a substrate for the production of the final product in the final engineered Y. lipolytica strain was created in this study. Finally, this synthetic consortium produced FAEE biodiesel at a titer of 4.8 mg/L under the optimum coculture conditions.

Comprehensive understanding of Saccharomyces cerevisiae phenotypes with whole-cell model WM_S288C

Biological network construction for Saccharomyces cerevisiae is a widely used approach for simulating phenotypes and designing cell factories. However, due to a complicated regulatory mechanism governing the translation of genotype to phenotype, precise prediction of phenotypes remains challenging. Here, we present WM_S288C, a computational whole-cell model that includes 15 cellular states and 26 cellular processes and which enables integrated analyses of physiological functions of Saccharomyces cerevisiae. Using WM_S288C to predict phenotypes of S. cerevisiae, the functions of 1140 essential genes were characterized and linked to phenotypes at five levels. During the cell cycle, the dynamic allocation of intracellular molecules could be tracked in real-time to simulate cell activities. Additionally, one-third of non-essential genes were identified to affect cell growth via regulating nucleotide concentrations. These results demonstrated the value of WM_S288C as a tool for understanding and investigating the phenotypes of S. cerevisiae.

A GFP-fusion coupling FACS platform for advancing the metabolic engineering of filamentous fungi

BACKGROUND

The filamentous fungus Trichoderma reesei, the most widely used cellulase producer, also has promising applications in lignocellulose-based biorefinery: consolidated bioprocessing for the production of high value-added products. However, such applications are thwarted by the time-consuming metabolic engineering processes (design-build-test-learn cycle) for T. reesei, resulted from (i) the spore separation-mediated purification as the multinucleate hyphae, (ii) transformant screening for high expression levels since unavailable of episomal expression system, and (iii) cases of inexpressible heterologous proteins.

RESULTS

In this study, a GFP-fusion coupled fluorescence-activated cell sorting (FACS) platform was established to speed up the build and test process of the DBTL cycle, by enabling rapid selection for expressible heterologous genes and bypassing both laborious spore separation and transformant screening. Here, the feasibility of flow cytometry in analyzing and sorting T. reesei cells harboring GFP-fused expressible protein was proven, as well as the application of the platform for constitutive promoter strength evaluation. As a proof-of-concept, the platform was employed to construct the first T. reesei strain producing fatty alcohol, resulting in up to 2 mg hexadecanol being produced per gram biomass. Pathway construction was enabled through rapid selection of functional fatty acyl-CoA reductase encoding gene Tafar1 from three candidate genes and strains with high expression level from spore pools. As a result of using this method, the total costed time for the build and test cycle using T. reesei, subsequently, reduced by approx. 75% from 2 months to 2 weeks.

CONCLUSION

This study established the GFP-fusion coupling FACS platform and the first filamentous fungal fatty alcohol-producing cell factory, and demonstrated versatile applications of the platform in the metabolic engineering of filamentous fungi, which can be harnessed to potentially advance the application of filamentous fungi in lignocellulose-based biorefinery.

Structural and Biochemical Studies of a Biocatalyst for the Enzymatic Production of Wax Esters

Wax esters are high-value products whose enzymatic synthesis is of increasing biotechnological interest. The fabrication of cell factories that mass-produce wax esters may provide a facile route towards a sustainable, and environment-friendly approach to a large-scale process for this commodity chemical. An expedient route for wax-ester biocatalysis may be facilitated by the action of enzymes termed wax ester synthases/diacylglycerol acyltransferases (WS/DGAT), which produce wax esters using fatty acids and alcohols as a precursor. In this work, we report the structure for a member of the WS/DGAT superfamily. The structural data in conjunction with bioinformatics and mutational analyses allowed us to identify the substrate binding pockets, and residues that may be important for catalysis. Using this information as a guide, we generated a mutant with preference towards shorter acyl-substrates. This study demonstrates the efficacy of a structure-guided engineering effort towards a WS/DGAT variant with preference towards wax esters of desired lengths.

Heterologous Production of Flavour and Aroma Compounds in Saccharomyces cerevisiae

Over the last two decades, rapid progress in the field of synthetic biology has opened several avenues for the heterologous de novo production of complex biological compounds, such as biofuels, pharmaceuticals, and food additives in microbial hosts. This minireview addresses the usage of the yeast Saccharomyces cerevisiae as a microbial cell factory for the production of flavour and aroma compounds, thereby providing a path towards a sustainable and efficient means of producing what are normally rare, and often expensive plant-derived chemicals.

Microbial synthesis of medium-chain chemicals from renewables

Linear, medium-chain (C8-C12) hydrocarbons are important components of fuels as well as commodity and specialty chemicals. As industrial microbes do not contain pathways to produce medium-chain chemicals, approaches such as overexpression of endogenous enzymes or deletion of competing pathways are not available to the metabolic engineer; instead, fatty acid synthesis and reversed β-oxidation are manipulated to synthesize medium-chain chemical precursors. Even so, chain lengths remain difficult to control, which means that purification must be used to obtain the desired products, titers of which are typically low and rarely exceed milligrams per liter. By engineering the substrate specificity and activity of the pathway enzymes that generate the fatty acyl intermediates and chain-tailoring enzymes, researchers can boost the type and yield of medium-chain chemicals. Development of technologies to both manipulate chain-tailoring enzymes and to assay for products promises to enable the generation of g/L yields of medium-chain chemicals.

Biosynthesis of the fatty acid isopropyl esters by engineered Escherichia coli

The fatty acid methyl esters and fatty acid ethyl esters are known as biodiesels which are considered to be renewable, nontoxic and biodegradable biofuels. However, the conventional biodiesels show a high crystallization temperature which is one of the most critical obstacles against the widespread biodiesel usage. The high crystallization temperature of biodiesel can be reduced by replacing the methyl or ethyl ester with an isopropyl moiety. Here we report on a strategy to establish biosynthesis of the fatty acid isopropyl esters(FAIPEs) from the simple substrate glucose in Escherichia coli with heterologous coexpression of atoB encoded acetyl-CoA acetyltransferase and atoAD encode acetoacetyl-CoA transferase from E. coli, ADC encode acetoacetate decarboxylase from Clostridium acetobutylicum, ADH encoded NADP-dependent alcohol dehydrogenase from Clostridium beijerinckii, 'TesA encoded a truncated fatty acyl-ACP thioesterase and FadD encoded fatty acyl-CoA synthetase from E. coli, and the WS/DGAT encoded acyltransferase from Acinetobacter baylyi strain ADP1. It was found that the yield of FAIPEs was up to 203.4mg/L and accounted for around 6.4% (wt/wt) of the dry cell weight. Our results indicates that it is a feasible strategy to improve the yield of FAIPEs by increasing fatty acyl-CoA availability in biosynthetic pathway and exhibit a promising method for production of biodiesels with good low-temperature flow properties.

Engineering Yarrowia lipolytica as a platform for synthesis of drop-in transportation fuels and oleochemicals

Harnessing lipogenic pathways and rewiring acyl-CoA and acyl-ACP (acyl carrier protein) metabolism in Yarrowia lipolytica hold great potential for cost-efficient production of diesel, gasoline-like fuels, and oleochemicals. Here we assessed various pathway engineering strategies in Y. lipolytica toward developing a yeast biorefinery platform for sustainable production of fuel-like molecules and oleochemicals. Specifically, acyl-CoA/acyl-ACP processing enzymes were targeted to the cytoplasm, peroxisome, or endoplasmic reticulum to generate fatty acid ethyl esters and fatty alkanes with tailored chain length. Activation of endogenous free fatty acids and the subsequent reduction of fatty acyl-CoAs enabled the efficient synthesis of fatty alcohols. Engineering a hybrid fatty acid synthase shifted the free fatty acids to a medium chain-length scale. Manipulation of alternative cytosolic acetyl-CoA pathways partially decoupled lipogenesis from nitrogen starvation and unleashed the lipogenic potential of Y. lipolytica Taken together, the strategies reported here represent promising steps to develop a yeast biorefinery platform that potentially upgrades low-value carbons to high-value fuels and oleochemicals in a sustainable and environmentally friendly manner.

Production of 1-decanol by metabolically engineered Yarrowia lipolytica

Medium-chain alcohols are used to produce solvents, surfactants, lubricants, waxes, creams, and cosmetics. In this study, we engineered the oleaginous yeast Yarrowia lipolytica to produce 1-decanol from glucose. Expression of a fatty acyl-CoA reductase from Arabidopsis thaliana in strains of Y. lipolytica previously engineered to produce medium-chain fatty acids resulted in the production of 1-decanol. However, the resulting titers were very low (<10mg/mL), most likely due to product catabolism. In addition, these strains produced small quantities of 1-hexadecanol and 1-octadecanol. Deleting the major peroxisome assembly factor Pex10 was found to significantly increase 1-decanol production, resulting in titers exceeding 500mg/L. It also increased 1-hexadecanoland and 1-octadecanol titers, though the resulting increases were less than those for 1-decanol. These results demonstrate that Y. lipolytica can potentially be used for the industrial production of 1-decanol and other fatty alcohols from simple sugars.