Survey of nonconventional yeasts for lipid and hydrocarbon biotechnology

Abstract

Non-conventional yeasts have an untapped potential to expand biotechnology and enable process development necessary for a circular economy. They are especially convenient for the field of lipid and hydrocarbon biotechnology because they offer faster growth than plants, easier scalability than microalgae and exhibit increased tolerance relative to some bacteria. The ability of industrial organisms to import and metabolically transform lipids and hydrocarbons are crucial in such applications. Here, we assessed the ability of 14 yeasts to utilize 18 model lipids and hydrocarbons from six functional groups and three carbon chain lengths. The studied strains covered 12 genera from nine families. Nine non-conventional yeast performed better than Saccharomyces cerevisiae, the most common industrial yeast. Rhodotorula toruloides, Candida maltosa, Scheffersomyces stipis and Yarowia lipolytica were observed to grow significantly better and on more types of lipid and lipid-molecules than other strains. They were all able to utilize mid to long-chain fatty acids, fatty alcohols, alkanes, alkenes and dicarboxylic acids, including 28 previously unreported substrates across the four yeasts. Interestingly, a phylogenetic analysis showed a short evolutionary distance between the R. toruloides and C. maltosa and S. stipitis, even though R. toruloides is classified under a different phylum. This work provides valuable insight into the lipid substrate range of non-conventional yeasts that can inform species selection decisions and viability of lipid feedstocks.

High-Temperature, Noncatalytic Oxidation of Polyethylene to a Fermentation Substrate Robustly Utilized by Candida maltosa

“…Remarkably, the growth of C. maltosa on TOD SF2 wax was statistically indistinguishable from growth on glucose, with a pairwise p-value of 0.06. Previous work showed that C. maltosa could achieve comparable growth to glucose with 1tetradecanol as the sole carbon source, 47 and this work now shows it can do the same with a complex mixture of hydrocarbons and other organic molecules.…”

“…These two species were used in this study because prior work characterized their substrate range and showed their ability to utilize hydrocarbons, fatty acids, and fatty alcohols, similar to the ones in the TOD composition, as their sole carbon source. 47 C. maltosa showed superior growth on TOD SF2 wax (final OD 600 of 2.0) compared to the other HDPE-derived substrates (final OD 600 of 0.64 for TOD SF1 wax, 0.32 for TOD liquid, 0.22 for pyrolysis SF1 wax, and 0.24 for pyrolysis SF2 wax; all with p-value <0.05 when compared to TOD SF2) as shown in Figure 3. Remarkably, the growth of C. maltosa on TOD SF2 wax was statistically indistinguishable from growth on glucose, with a pairwise p-value of 0.06.…”

“…These yeasts were selected based on a previous survey of utilization of compounds found in TOD substrates. 47 S. cerevisiae was included as a control because it is a common industrial yeast species.…”

“…cerevisiae NRRL Y-12632. These yeasts were selected based on a previous survey of utilization of compounds found in TOD substrates S.…”

“…C. maltosa and S. stipitis were selected for this task from a yeast survey that tested consumption of model compounds representative of some of the major components in the mixture of HDPE TOD product. 47 Importantly, through the introduction of oxygen into the thermal degradation process, microbial utilization was significantly enhanced while offering processing benefits. This novel approach to utilizing waste plastics serves as a platform for future research in the production of macronutrients for animal or human consumption.…”