Enhancement of Copper Uptake of Yeast Through Systematic Optimization of Medium and the Cultivation Process of Saccharomyces cerevisiae.

Copper is an essential trace element for living organisms. Copper enriched by yeast of Saccharomyces cerevisiae is regarded as the biologically available organic copper supplement with great potentiality for application. However, the lower uptake ratio of copper ions makes the production of copper enriched by yeast uneconomically and environmentally unfriendly. In this study, S. cerevisiae Cu-5 with higher copper tolerance and intracellular copper accumulation was obtained by screening of our yeast strains collection. To increase the uptake ratio of copper ions, the medium composition and cultivation conditions for strain Cu-5 were optimized systematically. A medium comprised of glucose, yeast extract, (NH4)2SO4, and inorganic salts was determined, then a novel cultivation strategy including pH control at 5.5 and increasing amounts of yeast extract for a higher concentration of copper ion in the medium was developed. The uptake ratios of copper ions were more than 90% after combining 50 to 100 mg/L copper ions with 3.5 to 5.0 g/L yeast extract, which is the highest until now and is conducive to the cost-effective and environmentally friendly production of bioactive copper in yeast-enriched form.

Treatment of vitamin K-dependent coagulation factor deficiency and subarachnoid hemorrhage.

BACKGROUND: In adults, vitamin K-dependent coagulation factor deficiency (VKCFD) increases in the recent years. We treated a VKCFD patient with subarachnoid hemorrhage, with favorable outcomes. METHODS: A 19-year-old male student with VKCFD was treated at our hospital. The initial treatment was injection of a large dose of vitamin K and fresh plasma, and then with oral high dose of vitamin K4. RESULTS: At 4 weeks after admission, the focus of hemorrhage subsided, neurological examination was normal, and the patient was discharged. CONCLUSIONS: VKCFD is rare and its diagnosis should be based on the history of the patient and the results of laboratory examinations. A large dose of vitamin K is the first choice of treatment.