Astaxanthin is an important ketocarotenoid widely used in industries.However,its application is limited because of its low yield.Sodium citrate(Na-citrate),one of the major carbon sources for microorganisms,can promot...Astaxanthin is an important ketocarotenoid widely used in industries.However,its application is limited because of its low yield.Sodium citrate(Na-citrate),one of the major carbon sources for microorganisms,can promote cell growth and product accumulation.The basidiomycetous red yeast Xanthophyllomyces dendrorhous was thus used to study the effect of Na-citrate on cell growth and astaxanthin synthesis.The highest biomass and astaxanthin yield(6.0 g/L and 22.5 mg/L)were obtained in shake-flask when 3 g/L Na-citrate was added at 24 h and were 1.8 and 2.0 times higher than those of the control group,respectively.Furthermore,metabolomics and real-time reverse transcription PCR(qRT-PCR)analysis were conducted to study the metabolic pathways of X.dendrorhous in response to Na-citrate.The qRT-PCR assay revealed that Na-citrate facilitated glucose consumption,promoted the metabolic flux from glycolysis,and regulated the tricarboxylic acid(TCA)cycle,providing more energy and substrates for the synthesis of astaxanthin.The gene analysis revealed that adding Na-citrate significantly upregulated the expression of six key genes(ICL,HMGS,crtE,crtYB,crtI,and crtS)involved in pathways related to astaxanthin biosynthesis.These results suggest that exogenous Na-citrate treatment is a potentially valuable strategy to stimulate astaxanthin production in X.dendrorhous.展开更多
Application of the computer image analysis for improving microbial viability assessment by plate count and fluorescence microscopy was investigated. Yeast cells were used as a model microorganism. The application of t...Application of the computer image analysis for improving microbial viability assessment by plate count and fluorescence microscopy was investigated. Yeast cells were used as a model microorganism. The application of the improved methods for the viability assessment of yeast cells after preservation by freezing and freeze-drying was demonstrated.展开更多
基金supported by the National Natural Science Foundation of China(32200047)the Key Program of Anhui Province Education Department(KJ2021A0711)the Natural Science Key Program of Bengbu Medical College(2020byzd025).
文摘Astaxanthin is an important ketocarotenoid widely used in industries.However,its application is limited because of its low yield.Sodium citrate(Na-citrate),one of the major carbon sources for microorganisms,can promote cell growth and product accumulation.The basidiomycetous red yeast Xanthophyllomyces dendrorhous was thus used to study the effect of Na-citrate on cell growth and astaxanthin synthesis.The highest biomass and astaxanthin yield(6.0 g/L and 22.5 mg/L)were obtained in shake-flask when 3 g/L Na-citrate was added at 24 h and were 1.8 and 2.0 times higher than those of the control group,respectively.Furthermore,metabolomics and real-time reverse transcription PCR(qRT-PCR)analysis were conducted to study the metabolic pathways of X.dendrorhous in response to Na-citrate.The qRT-PCR assay revealed that Na-citrate facilitated glucose consumption,promoted the metabolic flux from glycolysis,and regulated the tricarboxylic acid(TCA)cycle,providing more energy and substrates for the synthesis of astaxanthin.The gene analysis revealed that adding Na-citrate significantly upregulated the expression of six key genes(ICL,HMGS,crtE,crtYB,crtI,and crtS)involved in pathways related to astaxanthin biosynthesis.These results suggest that exogenous Na-citrate treatment is a potentially valuable strategy to stimulate astaxanthin production in X.dendrorhous.
文摘Application of the computer image analysis for improving microbial viability assessment by plate count and fluorescence microscopy was investigated. Yeast cells were used as a model microorganism. The application of the improved methods for the viability assessment of yeast cells after preservation by freezing and freeze-drying was demonstrated.
