Low-cost lipid production by an oleaginous yeast cultured in non-sterile conditions using model waste resources

Abstract

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.

Conversion of raw glycerol to microbial lipids by new Metschnikowia and Yarrowia lipolytica strains

“…2b). An increase of glycerol concentration (90 g/L), under the same fermentation conditions, was favorable for higher biomass production (5.5 g/L), as also reported by Santamauro et al (2014) (Fig. 2c).…”

“…Indeed, Santamauro et al (2014) obtained the maximum lipid production from M. pulcherrima in raw glycerol after an incubation at 25°C for 3 days followed by further 12 days at 15°C.…”

Oil palm and biodiversity: a situation analysis by the IUCN Oil Palm Task Force

“…There are commercially available alternatives to palm oil but they tend to be economically infeasible for the scale at which palm oil is being used for food and industrial purposes (17). A potential substitute may come in the form of the yeast, Metschnikowia pulcherrima, which is used as a biological control agent in the South African wine industry and is able to produce oil with a similar lipid profile to palm oil (18,19). …”

Palmiers à huile et biodiversité: analyse de la situation par le Groupe de travail de l’UICN sur les palmiers à huile

“…Il existe des alternatives commerciales à l'huile de palme, mais elles sont généralement non-viables économiquement, à l'échelle à laquelle l'huile de palme est utilisée pour l'alimentation ou dans l'industrie (17). La levure Metschnikowia pulcherrima, utilisée comme agent de contrôle biologique dans l'industrie vinicole sudafricaine et capable de produire une huile présentant un profil lipidique similaire à l'huile de palme, est l'un de ces possibles substituts (18,19). …”