海洋石油降解酵母的分离鉴定与降解特性

以原油为唯一碳源,采用富集培养、平板涂布分离、平板划线纯化及摇瓶复筛等方法,从表层海水或海泥中分离得到2株具有较强石油降解能力的菌株SYB-5和SYB-2. 根据菌落及菌体形态、生理生化特征和分子生物学分析、鉴定显示,SYB-5为季也蒙毕赤酵母(Meyerozyma guilliermondii/Pichia guilliermondii),SYB-2为长孢洛德酵母(Lodderomyces elongisporus). 对2株酵母菌的石油降解性能的研究结果表明,SYB-5和SYB-2以原油组分作为碳源,以(NH₄)₂SO₄和(NH₄)₃PO₄作为氮源,在ρ(NaCl)为30g/L、氧气充足的条件下,生长的最适温度分别为36和32℃,pH均为7.0. 在最适生长条件下,培养5d后的原油降解率分别达到45.8%和34.4%. 当2株菌混合培养时,培养5d的原油降解率可提高到53.9%,培养8d时达到56.4%,说明2株菌利用原油作碳源生长时具有协同作用. 

Isolation and Identification of Marine Petroleum-Degrading Yeast and Their Biodegradation Characteristics

Two petroleum-degrading yeast strains, SYB-5and SYB-2, were isolated from the oil terminal surface water and the mud, with crude oil as the sole carbon source via enrichment culture. SYB-5was identified as Meyerozyma guilliermondii (Pichia guilliermondii) and SYB-2was identified as Lodderomyces elongisporus through the techniques including morphology, physiological, biochemical characteristics, and the analysis of DNA sequences. Their optimal conditions for growth and degradation were set as:NaCl concentration 30g/L, (NH₄)₂SO_4and (NH₄)₃PO_4as nitrogen source, the temperature and pH value of 36℃ and 7.0for SYB-5, but 32℃ and 7.0for SYB-2. After 5-day incubation at shaking rate of 200r/min, the degradation rates of crude oil for these two strains were 45.8% and 34.4%, respectively. When co-culture of SYB-5and SYB-2, the degration rate for the 5-day incubation was improved to 53.9%, and that for 8-day incubation was up to 56.4%. This indicated that co-culture of SYB-5and SYB-2had a synergistic effect on the degradation of crude oil.