固定化海洋脲酶制备及其在尿素废水处理中的应用

doi:10.13560/j.cnki.biotech.bull.1985.2019-0254

摘要/Abstract

摘要： 为确定合适的海洋碱性脲酶固定化方案,并对固定化脲酶的尿素废水处理效果进行评估。分别用3种材料对脲酶进行包埋,测定其固定化效果及酶学性质,并筛选出最佳方案装柱运行。结果表明：采用海藻酸钠-CaCl₂包埋效果最佳,其固定化率达61.47%,酶的最适温度从55℃提高至70℃,最适pH从8.5提升至9.5,在35-85℃保存30 min或在pH 7-10.5保持6 h后酶活仍能保持在90%以上,在4℃保存半衰期超过3个月。处理装置在70℃时,尿素废水流量达19 mL/min,且初始尿素降解率为90.25%,连续运转35 d效率不变。游离脲酶经海藻酸钠固定化后最适温度、pH及耐热性、耐碱性提升最显著;运用该固定化海洋脲酶进行尿素废水处理是除化学法外一条有效途径。

关键词: 海洋脲酶, 固定化, 尿素, 废水处理

Abstract: The objective is to develop an appropriate immobilization strategy for marine alkaline urease and to provide technical assessments for urea wastewater treatment via the immobilized urease. The enzyme was immobilized by 3 kinds of materials,and the immobilization effects,enzyme properties were examined. The immobilized urease was loaded in a column for urea wastewater treatment and the operating parameters were optimized. Urease immobilized by alginate-CaCl₂ was the best with an immobilization rate reaching 61.47%. Comparing to the free urease with optimal temperature 55℃ and pH 8.5,the immobilized urease increased to 70℃,and pH 9.5,respectively,and sustained over 90% activity after incubating at 35-85℃ for 30 min or at pH 7-10.5 for 6 h. Furthermore,its half-life exceeded 3 months when stored at 4℃. The treatment apparatus achieved a flow rate of 19 mL/min at 70℃ with an initial urea decomposition rate of 90.25%,and the efficiency remained constant for 35 days. In conclusion,the optimal temperature and pH,the thermostability and the alkali resistance of the marine urease are much improved after being immobilized by alginate-CaCl₂. The urea wastewater treatment applying the immobilized marine urease represents a considerable alternative technique besides chemical method.

Key words: marine urease, immobilization, urea, wastewater treatment

刘长荣, 张风丽, 李志勇. 固定化海洋脲酶制备及其在尿素废水处理中的应用[J]. 生物技术通报, 2019, 35(9): 75-82.

LIU Chang-rong, ZHANG Feng-li, LI Zhi-yong. Immobilization of Marine Urease and Its Utilization in the Treatment of Urea Wastewater[J]. Biotechnology Bulletin, 2019, 35(9): 75-82.

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