Koti Sravanthi, Govumoni Sai Prashanthi, Gentela Jahnavi, Venkateswar Rao L
Department of Microbiology, Osmania University, Hyderabad, Telangana state 500 007 India.
Springerplus. 2016 Sep 13;5(1):1545. doi: 10.1186/s40064-016-3222-1. eCollection 2016.
The main aim of the present study was to mutate yeast strains, Pichia stipitis NCIM 3498 and Candida shehatae NCIM 3501 and assess the mutant's ability to utilize, ferment wheat straw hemicellulose with enhanced ethanol yield. The organisms were subjected to random mutagenesis using physical (ultraviolet radiation) and chemical (ethidium bromide) mutagens. The mutant and wild strains were used to ferment the hemicellulosic hydrolysates of wheat straw obtained by 2 % dilute sulphuric acid and enzymatic hydrolysis by crude xylanase separately. Among all the mutant strains, PSUV9 and CSEB7 showed enhanced ethanol production (12.15 ± 0.57, 9.55 ± 0.47 g/L and yield 0.450 ± 0.009, 0.440 ± 0.001 g/g) as compared to the wild strains (8.28 ± 0.54, 7.92 ± 0.89 g/L and yield 0.380 ± 0.006 and 0.370 ± 0.002 g/g) in both the hydrolysates. The mutant strains were also checked for their consistency in ethanol production and found stable for 19 cycles in hemicellulosic hydrolysates of wheat straw. A novel element in the present study was introduction of chemical mutagenesis in wild type as well as UV induced mutants. This combination of treatments i.e., UV followed by chemical mutagenesis was practically successful.
本研究的主要目的是对树干毕赤酵母NCIM 3498和嗜杀假丝酵母NCIM 3501酵母菌株进行诱变，并评估突变体利用、发酵小麦秸秆半纤维素以提高乙醇产量的能力。使用物理诱变剂（紫外线辐射）和化学诱变剂（溴化乙锭）对这些微生物进行随机诱变。分别使用突变菌株和野生菌株发酵通过2%稀硫酸和粗木聚糖酶酶解获得的小麦秸秆半纤维素水解产物。在所有突变菌株中，与野生菌株（8.28±0.54、7.92±0.89 g/L，产率0.380±0.006和0.370±0.002 g/g）相比，PSUV9和CSEB7在两种水解产物中均表现出更高的乙醇产量（12.15±0.57、9.55±0.47 g/L，产率0.450±0.009、0.440±0.001 g/g）。还检测了突变菌株乙醇生产的稳定性，发现其在小麦秸秆半纤维素水解产物中可稳定传代19次。本研究中的一个新元素是在野生型以及紫外线诱导的突变体中引入化学诱变。这种处理组合，即紫外线诱变后进行化学诱变，在实际应用中取得了成功。
