关键词: 培养条件, 比增长速率, 生化成份, 发状念珠藻

Abstract: Nostoc flagelliforme is a terrestrial filamentous nitrogen-fixing cyanobacterium that has been used as a health food and herbal medicine by Chinese and other Asian populations over centuries. The commercial source of N. flagelliforme biomss is harvesting from natural aquatic environments. Mass culture of N. flagelliforme in an engineered system is sought but has not been available, due in large to the lack of understanding the growth physiology of the organism under changing environments. In this study, the effect of temperature, nutrients and light intensity on growth and biochemical composition of Nostoc flagelliforme were investigated. The results indicated that growth rate and biochemical composition were influenced by temperature, nutrients and light intensity. Specific growth rates under 25℃ and 45 mmol/(m2×s) were the most rapid than under other conditions. Growth rates in the culture medium lacking N, P and Ca were of significant difference from the control BG11 medium (p<0.05). No obvious growth difference existed between Medium lacking K, lacking micronutrient As and the control medium. Content of exopolysaccharides (EPS) decreased accompanied with increasing of temperature. Low and high light intensities were helpful to EPS producing. Nutrients starvation was a great disadvantage for algae to produce EPS. Protein content at 25℃ was the highest among all temperature experiments. It increased accompanied with increasing of light intensity but decreased when cultured in the modified BG11 medium (one of nutriment ingredient was deficient). It could be concluded that 25℃ and 45 mmol/(m2×s) were optimal culture conditions and N, P and Ca were necessary for this algal growth.

Key words: culture conditions, specific growth rate, biochemical composition, Nostoc flagelliforme