Department of Microbiology-Centre of Excellence, Dr. Ram Manohar Lohia Avadh University, Faizabad 224001, Uttar Pradesh, India.
BMC Biotechnol. 2012 Jun 18;12:30. doi: 10.1186/1472-6750-12-30.
Sugarcane distilleries use molasses for ethanol production and generate large volume of effluent containing high biological oxygen demand (BOD) and chemical oxygen demand (COD) along with melanoidin pigment. Melanoidin is a recalcitrant compound that causes several toxic effects on living system, therefore, may be treated before disposal. The aim of this study was to isolate a potential thermotolerant melanoidin decolorizing yeast from natural resources, and optimized different physico-chemical and nutritional parameters.
Total 24 yeasts were isolated from the soil samples of near by distillery site, in which isolate Y-9 showed maximum decolorization and identified as Candida tropicalis by Microbial Type Culture Collection (MTCC) Chandigarh, India. The decolorization yield was expressed as the decrease in the absorbance at 475 nm against initial absorbance at the same wavelength. Uninoculated medium served as control. Yeast showed maximum decolorization (75%) at 45°C using 0.2%, glucose; 0.2%, peptone; 0.05%, MgSO4; 0.01%, KH₂PO₄; pH-5.5 within 24 h of incubation under static condition. Decolorizing ability of yeast was also confirmed by high performance liquid chromatography (HPLC) analysis.
The yeast strain efficiently decolorized melanoidin pigment of distillery effluent at higher temperature than the other earlier reported strains of yeast, therefore, this strain could also be used at industrial level for melanoidin decolorization as it tolerated a wide range of temperature and pH with very small amount of carbon and nitrogen sources.
糖厂用糖蜜生产乙醇，会产生大量含有高生物需氧量（BOD）和化学需氧量（COD）以及类黑精色素的废水。类黑精是一种难以生物降解的化合物，对生物系统会造成多种毒性效应，因此在处理之前需要进行处理。本研究旨在从天然资源中分离出一种潜在的耐热类黑精脱色酵母，并对不同理化和营养参数进行优化。
从附近糖厂附近的土壤样本中总共分离出 24 株酵母，其中分离株 Y-9 的脱色效果最佳，并通过印度昌迪加尔微生物类型培养收集中心（MTCC）鉴定为热带假丝酵母。脱色率表示在相同波长下初始吸光度与 475nm 处吸光度降低的百分比。未接种的培养基作为对照。在 45°C 下，酵母在 0.2%葡萄糖、0.2%蛋白胨、0.05%硫酸镁、0.01%磷酸二氢钾、pH-5.5 的条件下，在静置 24 小时内，使用 0.2%葡萄糖、0.2%蛋白胨、0.05%硫酸镁、0.01%磷酸二氢钾，可达到最大脱色率（75%）。在静态条件下，酵母的脱色能力也通过高效液相色谱（HPLC）分析得到了证实。
该酵母菌株能够在高于其他先前报道的酵母菌株的温度下有效地对废水中的类黑精色素进行脱色，因此，该菌株也可以在工业水平上用于类黑精的脱色，因为它能够耐受宽范围的温度和 pH 值，并且只需要少量的碳源和氮源。
