Improving an Alternative Glycerol Catabolism Pathway in Yarrowia lipolytica to Enhance Erythritol Production.

Engineering the glycerol-3-phosphate pathway could enhance erythritol production by accelerating glycerol uptake. However, little work has been conducted on the alternative dihydroxyacetone (DHA) pathway in Yarrowia lipolytica. Herein, this route was identified and characterized in Y. lipolytica by metabolomic and transcriptomic analysis. Moreover, the reaction catalyzed by dihydroxyacetone kinase encoded by dak2 was identified as the rate-limiting step. By combining NHEJ-mediated insertion mutagenesis with a push-and-pull strategy, Y. lipolytica strains with high-yield erythritol synthesis from glycerol were obtained. Screening of a library of insertion mutants allows the identification of a mutant with fourfold increased erythritol production. Overexpression of DAK2 and glycerol dehydrogenase GCY3 together with gene encoding transketolase and transaldolase from the nonoxidative part of the pentose phosphate pathway led to a strain with further increased productivity with a titer of 53.1 g/L and a yield 0.56 g/g glycerol, which were 8.1- and 4.2-fold of starting strain.

被引量：- 发表：1970

Rapid Fluorescence Assay for Polyphosphate in Yeast Extracts Using JC-D7.

Polyphosphate (polyP) is an intriguing molecule that is found in almost any organism, covering a multitude of cellular functions. In industry, polyP is used due to its unique physiochemical properties, including pH buffering, water binding, and bacteriostatic activities. Despite the importance of polyP, its analytics is still challenging, with the gold standard being 31P NMR. Here, we present a simple staining method using the fluorescent dye JC-D7 for the semi-quantitative polyP evaluation in yeast extracts. Notably, fluorescence response was affected by polyP concentration and polymer chain length in the 0.5-500 µg/mL polyP concentration range. Hence, for polyP samples of unknown chain compositions, JC-D7 cannot be used for absolute quantification. Fluorescence of JC-D7 was unaffected by inorganic phosphate up to 50 mM. Trace elements (FeSO4 > CuSO4 > CoCl2 > ZnSO4) and toxic mineral salts (PbNO3 and HgCl2) diminished polyP-induced JC-D7 fluorescence, affecting its applicability to samples containing polyP-metal complexes. The fluorescence was only marginally affected by other parameters, such as pH and temperature. After validation, this simple assay was used to elucidate the degree of polyP production by yeast strains carrying gene deletions in (poly)phosphate homeostasis. The results suggest that staining with JC-D7 provides a robust and sensitive method for detecting polyP in yeast extracts and likely in extracts of other microbes. The simplicity of the assay enables high-throughput screening of microbes to fully elucidate and potentially enhance biotechnological polyP production, ultimately contributing to a sustainable phosphorus utilization.

被引量：- 发表：1970

pSPObooster: A Plasmid System to Improve Sporulation Efficiency of Saccharomyces cerevisiae Lab Strains.

Common Saccharomyces cerevisiae lab yeast strains derived from S288C have meiotic defects and therefore are poor sporulators. Here, we developed a plasmid system containing corrected alleles of the MKT1 and RME1 genes to rescue the meiotic defects and show that standard BY4741 and BY4742 strains containing the plasmid display faster and more efficient sporulation. The plasmid, pSPObooster, can be maintained as an episome and easily cured or stably integrated into the genome at a single locus. We demonstrate the use of pSPObooster in low- and high-throughput yeast genetic manipulations and show that it can expedite both procedures without impacting strain behavior.

被引量：- 发表：1970

Marker-free genomic editing in Saccharomyces cerevisiae using universal donor templates and multiplexing CRISPR-CAS9.

被引量：- 发表：1970

In vivo CRISPR-Cas9 expression in Candida glabrata, Candida bracarensis, and Candida nivariensis: A versatile tool to study chromosomal break repair.

The CRISPR-Cas9 system is extremely useful for genome editing in many species, including the model yeast Saccharomyces cerevisiae, and other yeast species. We have previously reported the use of an inducible CRISPR-Cas9 system in Candida glabrata, which allows genome editing but also the study of double-strand break (DSB) repair. We report, in this study, a comparable system for C. glabrata, relying on a new plasmid, which is more stable than the previous one. We also report the use of this plasmid to induce DSBs in two additional human pathogens, Candida bracarensis and Candida nivariensis. We examine lethality induced by an in vivo DSB in the three species and describe the different types of nonhomologous end-joining (NHEJ) events detected in these three pathogens.

被引量：- 发表：1970