Browsing by Author "Visscher, B."

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Production of tailor-made enzymes to facilitate lipid extraction from the oleaginous yeast Schwanniomyces occidentalis
Heshof, R. ; Visscher, B. ; Zilver, E. van de ; Vondervoort, R. van de ; Keulen, F. van ; Delahaije, R.J. ; Wind, R.D.
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.
Overexpression of delta-12 desaturase in the yeast Schwanniomyces occidentalis enhances the production of linoleic acid.
Lamers, W.L. ; Visscher, B. ; Weusthuis, R.A. ; Francke, C. ; Wijffels, R.H. ; Lokman, B.C.
2019, Article / Letter to editor (Bioresource Technology, vol. 289, (2019), pp. 121672)The oleaginous yeast Schwanniomyces occidentalis was previously isolated because of its excellent suitability to convert lignocellulosic hydrolysates into triacyl glycerides: it is able to use a broad range of sugars and is able to tolerate high concentrations of lignocellulosic hydrolysate inhibitors. Compared to other oleaginous yeasts S. occidentalis however produces a low content of unsaturated fatty acids. We show here that the linoleic acid content can be significantly improved by (over)expression Δ12-desaturases derived from S. occidentalis and Fusarium moniliforme. Expression was stable for the homologous expression but decreased during heterologous expression. Both homologous and heterologous expression of mCherry-Δ12-desaturase led to a 4-fold increase in linoleic acid from 0.02 g/g biomass to 0.08 g/g biomass resulting in the production of 2.23 g/L and 2.05 g/L of linoleic acid.
Large-scale cultivation of Caenorhabditis elegans in a bioreactor using a labor-friendly fed-batch approach.
Heshof, R. ; Visscher, B. ; Prömel, S. ; Hughes, S.L.
2019, Article / Letter to editor (vol. 67, iss. 1, (2019), pp. 33-39)Caenorhabditis elegans is an invertebrate model organism used in many areas of biology including developmental biology and the identification of molecular mechanisms and pathways. However, several experimental approaches require large quantities of worms, which is limiting and time-consuming. We present a protocol that uses modern fermentation methodology to effectively produce large numbers of C. elegans using a 7-l bioreactor in a fed-batch cultivation procedure. The production is modular and flexible as well as being a self-controlled system, thus not much labor is required until harvesting C. elegans. The high-yield worm cultivation is flexible and simple to amend, and now allows for the extended application of C. elegans as a model organism and expression system, including large-scale protein production.

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Browsing by Author "Visscher, B."

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