Bioethanol production from Yarrowia lipolytica Po1g biomass

Bioenergy production from yeast through a thermo-chemical platform

Alternative fuels are urgently needed to mitigate greenhouse gas emissions. This study was conducted to recover bioenergy from non-edible feedstock, an oleaginous yeast biomass obtained during fed-batch cultivation of Yarrowia lipolytica. Yeast oil (lipids) was extracted from the harvested biomass and readily converted into biodiesel using the non-catalytic transesterification method. The conversion yield of the convertible lipids was 97.4 wt%, even with a high content of unidentified impurities (> 12.7 wt%). To maximize bioenergy production and minimize waste generation, the yeast biomass residue after oil extraction was used as a feedstock for pyrolysis. The yield of flammable gases (H2, CO, and CH4) produced from catalytic pyrolysis of residual biomass was 194.7 mmol under CO2 conditions, a 14.3 % increase compared to that under N2 conditions. Consequently, the use of a thermochemical platform (non-catalytic transesterification and catalytic pyrolysis under CO2 conditions) for yeast biomass valorization enhances bioenergy production and minimizes waste generation.

Molecular Identification and Biochemical Characterization of Novel Marine Yeast Strains with Potential Application in Industrial Biotechnology

Cell-based agriculture is an emerging and attractive alternative to produce various food ingredients. In this study, five strains of marine yeast were isolated, molecularly identified and biochemically characterized. Molecular identification was realized by sequencing the DNA ITS1 and D1/D2 region, and sequences were registered in GenBank as Yarrowia lipolytica YlTun15, Rhodotorula mucilaginosa RmTun15, Candida tenuis CtTun15, Debaryomyces hansenii DhTun2015 and Trichosporon asahii TaTun15. Yeasts showed protein content varying from 26% (YlTun15) to 40% (CtTun15 and DhTun2015), and essential amino acids ranging from 38.1 to 64.4% of the total AAs (CtTun15-YlTun15, respectively). Lipid content varied from 11.15 to 37.57% with substantial amount of PUFA (>12% in RmTun15). All species had low levels of Na (<0.15 mg/100 g) but are a good source of Ca and K. Yeast cytotoxic effect was investigated against human embryonic kidney cells (HEK 293); results showed improved cell viability with all added strains, indicating safety of the strains used. Based on thorough literature investigation and yeast composition, the five identified strains could be classified not only as oleaginous yeasts but also as single cell protein (SCP) (DhTun2015 and CtTun15) and single cell oil (SCO) (RmTun15, YlTun15 and TaTun15) producers; and therefore, they represent a source of alternative ingredients for food, feed and other sectors.

Food-related applications of Yarrowia lipolytica

Yarrowia lipolytica is a non-pathogenic generally regarded as safe yeast. It displays unique physiological as well as biochemical properties that are relevant in food-related applications. Strains naturally associated with meat and dairy products contribute towards specific textures and flavours. On some occasions they cause food spoilage. They produce food-additives such as aroma compounds, organic acids, polyalcohols, emulsifiers and surfactants. The yeast biomass has been projected as single cell oil and single cell protein. Y. lipolytica degrades or upgrades different types of food wastes and in some cases, value-added products have also been obtained. The yeast is thus involved in the manufacture of food stuffs, making of food ingredients, generation of biomass that can be used as food or feed and in the effective treatment of food wastes. On account of all these features, this versatile yeast is of considerable significance in food-related applications.