BackgroundThe yeast Metschnikowia pulcherrima, previously utilised as a biological control agent, was evaluated for its potential to produce lipids for biofuel production.ResultsCultivation in low cost non-sterile conditions was achieved by exploiting its ability to grow at low temperature and pH and to produce natural antimicrobial compounds. Although not previously classified as oleaginous, a combination of low temperature and restricted nutrient availability triggered high levels of oil production in M. pulcherrima cultures. This regime was designed to trigger the sporulation process but prevent its completion to allow the accumulation of a subset of a normally transitional, but oil-rich, ‘pulcherrima’ cell type. This approach resulted in yields of up to 40% lipid, which compares favourably with other oleaginous microbes. We also demonstrate that M. pulcherrima metabolises glycerol and a diverse range of other sugars, suggesting that heterogeneous biomass could provide a suitable carbon source. M. pulcherrima also grows well in a minimal media containing no yeast extract. Finally, we demonstrate the potential of the yeast to produce lipids inexpensively on an industrial scale by culturing the yeast in a 500 L, open air, tank reactor without any significant contamination.ConclusionsThe production of antimicrobial compounds coupled to efficient growth at low temperature and pH enables culture of this oleaginous yeast in inexpensive, non-sterile conditions providing a potential route to economic biofuel production.

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Thiol-ene 'click' reactions have been initiated for a range of primary alkenes using ultrasound in both toluene and water. The method is particularly effective in aqueous solutions in the presence of air.

Palm oil production is a leading contributor to tropical deforestation, resulting in habitat destruction, increased carbon dioxide emissions, and local smog clouds across South East Asia. Palm oil is widely used for food, as a biofuel precursor, and in soaps and cosmetics. The global demand for palm oil is approximately 57 m tonnes a−1 and is steadily increasing. Alternatively, oleaginous yeast offers a highly credible renewable substitute. Over 80 species of oleaginous yeast are known, many of which have been demonstrated to catabolize a wide range of mono‐ and oligosaccharides in lignocellulose hydrolyzates. Many of the yeasts have demonstrated a high tolerance to furfurals and organic acid inhibitors and can be cultured at low pH, ideal for the industrial production of oil from lignocellulosic sources such as stover, forestry wastes, or energy crops. While the majority of the yeasts produce predominantly monounsaturated esters, some species are capable of producing oils higher in saturates akin to palm oil. While the manufacture of yeast oils on an industrial scale has been demonstrated, currently no large‐scale production from lignocellulose exists; however, through further strain selection, metabolic engineering, and valorization of co‐products, the production of a substitute oil from yeast is potentially feasible. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd

A range of microbial oils were cross-metathesized with ethene using Hoveyda−Grubbs second-generation catalyst. The products formed from the microbial oils were compared to alternative firstand second-generation oils. Upon separation, three separate fractions were produced: an alkene hydrocarbon fraction or aviation fuel fraction (AFF), a shorterchain triglyceride fraction that upon transesterification was suitable as a road transport fuel (road transport fraction, RTF), and a volatile short-chain alkene fraction (gas phase fraction, GPF). The fuel fractions were purified through distillation and compared to the relevant fuel standards. Though there was variation for the RTF because of the presence of long-chain saturates, all the RTF produced fell within the ASTM standard for biodiesel. The AFF was found to be highly suitable for aviation, falling entirely within the DEF-STAN fuel standard. In addition, the AFF possessed an energy density higher than that of Jet A-1, whereas 1-decene was found to have an oxidative stability higher than that of jet fuel. Finally, the GPF was found to predominantly contain propene, butene, and pentadiene isomers, all of which have application in the polymer industry. With further development, this process could provide the basis for a microbial oil biorefinery for the production of sustainable biofuels and polymer precursors.