Torulopsis sp．ERY237产赤藓糖醇工艺条件的研究

以Torulopsis sp.ERY237作为出发菌株,考察了不同碳源、氮源、无机盐类以及温度等因素对菌种产赤藓糖醇的影响,建立和优化了赤藓糖醇摇瓶发酵培养基配方、发酵工艺条件,同时研究了发酵过程中菌体生物量、pH值、产物浓度的动态变化。结果表明,菌株的最适培养基配方为(g/L):葡萄糖300,玉米浆3.5,C_([Cu^(2+)])1.5,C_([Mn^(2+)])10;适宜的培养条件为初始pH值自然,温度30℃,装液量50 mL/500 mL,转速200 r/min,在此条件下培养132 h赤藓糖醇产量达87.8 g/L,是优化前产量的1.9倍,发酵时间缩短了12 h。

Application of response surface methodology in medium optimization for pyruvic acid production of Torulopsis glabrata TP19 in batch fermentation

Response surface methodology (RSM) was used to optimize the fermentation medium for enhancing pyruvic acid production by Torulopsis glabrata TP19. In the first step of optimization, with Plackett-Burman design, ammonium sulfate, glucose and nicotinic acid were found to be the important factors affecting pyruvic acid production significantly. In the second step, a 23 full factorial central composite design and RSM were applied to determine the optimal concentration of each significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the critical components were obtained as follows: ammonium sulfate 0.7498 (10.75 g/L), glucose 0.9383 (109.38 g/L) and nicotinic acid 0.3633 (7.86 mg/L) with a predicted value of maximum pyruvic acid production of 42.2 g/L. Under the optimal conditions, the practical pyruvic acid production was 42.4 g/L. The determination coefficient (R2) was 0.9483, which ensures adequate credibility of the model. By scaling up fermentation from flask to jar fermentor, we obtained promising results.

铁红圆酵母属两个类群的培养特征初步研究

通过超滤膜过滤法，在大连市黑石礁海域２５００米以内，分离到白色与铁红圆酵母两类海洋酵母。铁红圆酵母分属于Ｔｏｒｕｌｏｐｓｉｓｐｕｌｃｅｒｒｉｍａ类群和Ｔｏｒｕｌｏｐｓｉｓｃａｎｄｉｄａ类群。葡萄糖——蛋白胨——酵母膏液体培养基静止培养条件下，Ｔ．ｐｕｌｃｅｒｒｉｍａ类群培养五天半，活酵母数量达到第一次高峰，为１．２×１０￣８／ｍｌ，大约在八天半之后，达到最高数量，为２．０×１０８／ｍｌ。Ｔ．ｃａｎｄｉｄａ类群，培养大约二天半后，酵母数量达到第一次高峰，为１．８×１０￣７／ｍｌ，培养大约十天半，活细胞数达到最高峰，为１．２×１０￣（－８）／ｍｌ。由于铁红园酵母具有易培性，耐不良环境能力强的优点，作为未来水产养殖业幼体饵料微生物具有广泛地应用前景。