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621.
622.
谷氨酸棒杆菌合成新型生物絮凝剂分批发酵过程的溶氧控制模式 总被引:2,自引:1,他引:1
在3L发酵罐上系统研究溶氧水平对谷氨酸棒杆菌菌体生长及新型生物絮凝剂REA 11合成的影响,提出生物絮凝剂REA 11合成的分阶段供氧控制策略:发酵过程0~16h维持体积传氧系数kLa为100h-1,16h后降低kLa为40h-1至发酵结束,整个发酵过程通气量保持在1L·L-1·min-1.采用该分阶段供氧控制策略,生物絮凝剂最终产量达到900mg·L-1,发酵周期缩短到30h,比恒定kLa为40h-1条件下的REA 11产量(549mg·L-1)提高了64%,产率提高了45%,生产强度也比kLa恒定为40h-1,100h-1和200h-1的分批发酵过程分别提高了81 2%,120%和420%,实现了高细胞生长速率和高产物产率的统一. 相似文献
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Tong Liu Shi-yong Yao Zhong-Yi Yin Xu-Xu Zheng Yu Shen 《Environmental science and pollution research international》2016,23(8):7132-7137
The seed of Zanthoxylum bungeanum (Z. bungeanum) is a by-product of pepper production and rich in unsaturated fatty acid, cellulose, and protein. The seed oil obtained from traditional producing process by squeezing or extracting would be bad quality and could not be used as edible oil. In this paper, a new preparation method of Z. bungeanum seed kernel oil (ZSKO) was developed by comparing the advantages and disadvantages of alkali saponification-cold squeezing, alkali saponification-solvent extraction, and alkali saponification-supercritical fluid extraction with carbon dioxide (SFE-CO2). The results showed that the alkali saponification-cold squeezing could be the optimal preparation method of ZSKO, which contained the following steps: Z. bungeanum seed was pretreated by alkali saponification under the conditions of adding 10 %NaOH (w/w), solution temperature was 80 °C, and saponification reaction time was 45 min, and pretreated seed was separated by filtering, water washing, and overnight drying at 50 °C, then repeated squeezing was taken until no oil generated at 60 °C with 15 % moisture content, and ZSKO was attained finally using centrifuge. The produced ZSKO contained more than 90 % unsaturated fatty acids and no trans-fatty acids and be testified as a good edible oil with low-value level of acid and peroxide. It was demonstrated that the alkali saponification-cold squeezing process could be scaled up and applied to industrialized production of ZSKO. 相似文献
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对某石化企业含腈废水的处理工艺进行了评估,从污染物的来源、组成、处理效果等方面研究了污染物的转化规律,揭示了现有工艺在含腈废水处理过程中的问题。实验结果表明:该企业污水处理场的废水来源较多,丙烯腈生产废水经四效蒸发系统处理后的出水是其污染物的主要来源,含有相对较多的含氮共轭体系;与其他废水混合后,经氨化作用,有机腈转变为有机胺和铵盐;A/O工段矿化度较高,COD的去除率高达73.0%,但有机胺含量仍较高;在缺氧池—生物流化池—硝化池工段,COD进一步被去除,胺类物质浓度大幅降低,但总氮脱除效果并不理想。 相似文献
629.
Chao Tai Shaodong Zhang Jing Wang Yongguang Yin Jianbo Shi Haoxian Wu Yuxiang Mao 《Environmental Chemistry Letters》2017,15(3):515-523
Singlet oxygen (1O2) and hydroxyl radical (·OH) play an important role in the degradation of pollutants in surface waters. However, the mechanism underlying the photochemical generation of 1O2 and ·OH in wastewaters is poorly known. Here we studied the photo-induced generation of 1O2 and ·OH in different sewage treatment plant units. The correlation between the generation of 1O2 and ·OH and the water constituents was discussed. Our results show that in sewage units the 1O2 formation rate ranges from 2.19 × 10?8 to 6.74 × 10?8 mol L?1 s?1, and the ·OH formation rate ranges from 1.7 × 10?11 to 3.06 × 10?10 mol L?1 s?1. The average 1O2 formation rates in the various sewage units are similar to those in wetland and estuarine waters containing rich dissolved organic matter and 2–4 times higher than those in lake and seawater samples. The average ·OH formation rates of the sewage units are 5–50 times higher than for other water samples reported. The ·OH generation rate increased with the iron content with a correlation coefficient of 0.85, which indicates that the photo-Fenton reaction plays a dominant role in ·OH generation in sewage wastewater. 相似文献
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Hu Xia-Lin Bao Yi-Fan Hu Jun-Jian Liu You-Yu Yin Da-Qiang 《Environmental science and pollution research international》2017,24(17):14889-14902
Environmental Science and Pollution Research - Pharmaceuticals in drinking water sources have raised significant concerns due to their persistent input and potential human health risks. The... 相似文献