2020, Article / Letter to editor (vol. 10, iss. 1, (2020), pp. 1-11)Due to the depletion of fossil fuel resources and concern about increasing atmospheric CO2 levels, the production of microbial oil as source for energy and chemicals is considered as a sustainable alternative. A promising candidate strain for the production of microbial oil is the oleaginous yeast Schwanniomyces occidentalis CBS 2864. To compete with fossil resources, cultivation and processing of S. occidentalis requires improvement. Currently, different cell wall disruption techniques based on mechanical, chemical, physiological, and biological methods are being investigated using a variety of oil producing yeasts and microalgae. Most of these techniques are not suitable for upscaling because they are technically or energetically unfavorable. Therefore, new techniques have to be developed to overcome this challenge. Here, we demonstrate an effective mild enzymatic approach for cell disruption to facilitate lipid extraction from the oleaginous yeast S. occidentalis. Most oil was released by applying 187 mg L−1 tailor-made enzymes from Trichoderma harzianum CBS 146429 against the yeast cell wall of S. occidentalis at pH 5.0 and 40 °C with 4 h of incubation time after applying 1 M NaOH as a pretreatment step.
2016, Article / Letter to editor (vol. 16, iss. 1, (2016), pp. 45)Background
Oleaginous yeast species are an alternative for the production of lipids or triacylglycerides (TAGs). These yeasts are usually non-pathogenic and able to store TAGs ranging from 20 % to 70 % of their cell mass depending on culture conditions. TAGs originating from oleaginous yeasts can be used as the so-called second generation biofuels, which are based on non-food competing “waste carbon sources”.
Results
In this study the selection of potentially new interesting oleaginous yeast strains is described. Important selection criteria were: a broad maximum temperature and pH range for growth (robustness of the strain), a broad spectrum of carbon sources that can be metabolized (preferably including C-5 sugars), a high total fatty acid content in combination with a low glycogen content and genetic accessibility.
Conclusions
Based on these selection criteria, among 24 screened species, Schwanniomyces occidentalis (Debaromyces occidentalis) CBS2864 was selected as a promising strain for the production of high amounts of lipids.