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- Holkenbrink, Carina, et al.
(author)
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Production of moth sex pheromones for pest control by yeast fermentation
- 2020
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In: Metabolic Engineering. - : Elsevier BV. - 1096-7176. ; 62, s. 312-321
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Journal article (peer-reviewed)abstract
- The use of insect sex pheromones is an alternative technology for pest control in agriculture and forestry, which, in contrast to insecticides, does not have adverse effects on human health or environment and is efficient also against insecticide-resistant insect populations. Due to the high cost of chemically synthesized pheromones, mating disruption applications are currently primarily targeting higher value crops, such as fruits. Here we demonstrate a biotechnological method for the production of (Z)-hexadec-11-en-1-ol and (Z)-tetradec-9-en-1-ol, using engineered yeast cell factories. These unsaturated fatty alcohols are pheromone components or the immediate precursors of pheromone components of several economically important moth pests. Biosynthetic pathways towards several pheromones or their precursors were reconstructed in the oleaginous yeast Yarrowia lipolytica, which was further metabolically engineered for improved pheromone biosynthesis by decreasing fatty alcohol degradation and downregulating storage lipid accumulation. The sex pheromone of the cotton bollworm Helicoverpa armigera was produced by oxidation of fermented fatty alcohols into corresponding aldehydes. The resulting yeast-derived pheromone was just as efficient and specific for trapping of H. armigera male moths in cotton fields in Greece as a conventionally produced synthetic pheromone mixture. We further demonstrated the production of (Z)-tetradec-9-en-1-yl acetate, the main pheromone component of the fall armyworm Spodoptera frugiperda. Taken together our work describes a biotech platform for the production of commercially relevant titres of moth pheromones for pest control via yeast fermentation.
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3. |
- Stovicek, Vratislav, et al.
(author)
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Rational and evolutionary engineering of Saccharomyces cerevisiae for production of dicarboxylic acids from lignocellulosic biomass and exploring genetic mechanisms of the yeast tolerance to the biomass hydrolysate
- 2022
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In: Biotechnology for Biofuels and Bioproducts. - : Springer Science and Business Media LLC. - 2731-3654. ; 15:1
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Journal article (peer-reviewed)abstract
- Background: Lignosulfonates are significant wood chemicals with a $700 million market, produced by sulfite pulping of wood. During the pulping process, spent sulfite liquor (SSL) is generated, which in addition to lignosulfonates contains hemicellulose-derived sugars—in case of hardwoods primarily the pentose sugar xylose. The pentoses are currently underutilized. If they could be converted into value-added chemicals, overall economic profitability of the process would increase. SSLs are typically very inhibitory to microorganisms, which presents a challenge for a biotechnological process. The aim of the present work was to develop a robust yeast strain able to convert xylose in SSL to carboxylic acids. Results: The industrial strain Ethanol Red of the yeast Saccharomyces cerevisiae was engineered for efficient utilization of xylose in a Eucalyptus globulus lignosulfonate stream at low pH using CRISPR/Cas genome editing and adaptive laboratory evolution. The engineered strain grew in synthetic medium with xylose as sole carbon source with maximum specific growth rate (µmax) of 0.28 1/h. Selected evolved strains utilized all carbon sources in the SSL at pH 3.5 and grew with µmax between 0.05 and 0.1 1/h depending on a nitrogen source supplement. Putative genetic determinants of the increased tolerance to the SSL were revealed by whole genome sequencing of the evolved strains. In particular, four top-candidate genes (SNG1, FIT3, FZF1 and CBP3) were identified along with other gene candidates with predicted important roles, based on the type and distribution of the mutations across different strains and especially the best performing ones. The developed strains were further engineered for production of dicarboxylic acids (succinic and malic acid) via overexpression of the reductive branch of the tricarboxylic acid cycle (TCA). The production strain produced 0.2 mol and 0.12 mol of malic acid and succinic acid, respectively, per mol of xylose present in the SSL. Conclusions: The combined metabolic engineering and adaptive evolution approach provided a robust SSL-tolerant industrial strain that converts fermentable carbon content of the SSL feedstock into malic and succinic acids at low pH.in production yields reaching 0.1 mol and 0.065 mol per mol of total consumed carbon sources. Moreover, our work suggests potential genetic background of the tolerance to the SSL stream pointing out potential gene targets for improving the tolerance to inhibitory industrial feedstocks.
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