• Applied Biological Chemistry
• /
• 제36권5호
• /
• pp.332-338
• /
• 1993

리보플라빈을 생산하기 위하여 Ashbya gosspii NRRL Y-1056의 균주개량을 시도하였으며 선발한 변이주 Ashbua gossypii JAG-13에 의한 리보플라빈의 생산시의 최적 배지조성 및 배양조건을 결정하였다. 최적 배지조성은 9%의 옥수수 기름, 3%의 젤라톤, 4%의 CSL, 0.3%의 글리신, 0.2%의 자당 지방산 에스테르 S770 였다. 배양배지의 초기 pH와 최적 배양온도는 각각 pH 6.5 와 $28^{\circ}C$였다. 산소의 공급은 리보플라빈의 생산에 필수적이었으나 과도한 산소의 공급은 오히려 리보플라빈의 생산을 저해하였다. Ashbya gosspii JAG-13을 위와같은 조건에서 생물배양기를 이용하여 12일간 배양하여 6.9 mg/ml의 리보플라빈을 생산하였다.

• Genomics & Informatics
• /
• 제4권2호
• /
• pp.80-86
• /
• 2006

It is clear that the construction of large insert DNA libraries is important for map-based gene cloning, the assembly of physical maps, and simple screening for specific genomic sequences. The bacterial artificial chromosome (BAC) system is likely to be an important tool for map-based cloning of genes since BAC libraries can be constructed simply and analyzed more efficiently than yeast artificial chromosome (YAC) libraries. BACs have significantly expanded the size of fragments from eukaryotic genomes that can be cloned in Escherichia coli as plasmid molecules. To facilitate the isolation of molecular-biologically important genes in Ashbya gossypii, we constructed Ashbya chromosome-specific BAC libraries using pBeloBAC11 and pBACwich vectors with an average insert size of 100 kb, which is equivalent to 19.8X genomic coverage. pBACwich was developed to streamline map-based cloning by providing a tool to integrate large DNA fragments into specific sites in chromosomes. These chromosome-specific libraries have provided a useful tool for the further characterization of the Ashbya genome including positional cloning and genome sequencing.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제6권2호
• /
• pp.75-88
• /
• 2001

In this paper, the microbial production of riboflavin is reviewed and includes descriptions of riboflavin overproducers, and the biosynthesis and details of the key-enzyme genes related to riboflavin. There kinds of riboflavin overproducers are known; Bacillus subtilis and Candida famate utilize glucose as a carbon source, but the fungus Ashbya gossypii requires plant oil as its sole carbon source. The starting material in ribofalvin biosynthesis is guanosine triphospate (GTP), which is converted to riboflavin through six enzymatic reactions. Though Bacillus subtilis, Candida famate, and Ashbya gossypii operate via different pathways until GTP, they follow the same pathway from GTP to riboflavin. From the metabolic viewpoint, with respect to improved riboflavin production, the supplementation of GTP, aprocess-limiting precursor must be considered. The GTP fluxes originate from three sources, serine, threonine and glyoxylate cycles. The development of pathways to strengthen GTP supplementation using biotechnological techniques remains an issue fro future research.

• 한국미생물·생명공학회지
• /
• 제21권6호
• /
• pp.615-621
• /
• 1993

In order to maximize the riboflavin production by a mutant strain Ashbya gosspyii, the optimization of medium and fed-batch fermentation were performed. As carbon sources, glucose and soybean oil were necessary for the riboflavin overproduction. Optimal concentrations of glucose and soybean oil in the flask cultures were found to be 3.0% and 0.5%, respectively, in a complex medium containing corn steep liquor(CLS) 1%. Among the various organic nitrogen sources tested, CSL was the most effective one both for the cell growth and riboflavin overproduction.

• 미생물학회지
• /
• 제23권3호
• /
• pp.167-171
• /
• 1985

E. coli에서 ribosyl-HTP(hydroxytriamino pyrimidine)를 GTP로 부터 합성하는 효소 GTP cyclohydrolase II가 발견된 뒤 riboflavin의 ribityl group이 guanine nucleotide의 ribosyl group에서 직접 유래한다는 가설이 제안되었다. 본 연구에서는$(U- ^{14}C)$ guanosine을 media에 첨가하여 배양한 riboflavin overproducer 균주 Ashybya 에서 추출 정제한 riboflavin과 RNA에 각각 Incorporate된 guanosine label의 specific radioactivity를 비교 측정함으 로써 ribity I group 이 guanosine에서 기훤한다는 결과를 얻을 수 있었다. 이는 GTP cyclohydrolase II가 riboflavin 생합성의 초기 단계에서 직접 관여한다는 가설을 지지해 주는 것이다.