摘要
本研究从连云港海泥中筛选产普鲁兰酶菌株,利用形态学、生理生化特征、基因序列(16S rRNA和gyr B)进行分析鉴定。利用产酶菌株发酵制备普鲁兰酶,初步纯化后分析其酶学性质。利用该普鲁兰酶粗提物对海带多糖进行水解,并对其水解产物进行抗氧化活性分析。结果表明:筛选得到一株产普鲁兰酶的巨大芽孢杆菌P6(Bacillus megaterium),经发酵纯化后普鲁兰酶比活力为62.3 U/mg,分子量约为43 k Da。该酶的最适反应温度为45℃,最适p H为6.5,在温度40℃下保温5 h,相对残余酶活达95%以上,而60℃下保温1 h,酶全部失活。在p H6~7.5之间保温12 h后,该酶仍有40%以上的相对残余酶活。DPPH和·OH自由基清除实验表明:海带多糖经普鲁兰酶水解后抗氧化活性显著增强(p<0.05),为普鲁兰酶在食品工业中的应用研究提供了新的方向。
A pullulanase producing strain was isolated from the beach mud of Lianyungang. The strain was identified by morphology, physiological and biochemical analysis and sequencing of 16S rRNA and gyrB genes.The pullulanase was obtained by fermentation and preliminarily purified.The enzymatic properties of the pullulanase were then characterized. Laminaria japonica polysaccharide was hydrolyzed by the crude pullulanase.The antioxidant activity of the hydrolysate of Laminaria japonica polysaccharide was studied. Results showed that the strain P6 was identified as Bacillus megaterium. The specific activity of the pullulanase prepared by fermentation and purification reached 62.3 U/rag.The molecular weight of the enzyme was about 43 kDa.The optimal temperature and pH for the pullulanase activity were 45 ℃ and 6.5 ,respectively.After incubation at 40 ℃ for 5 h,the remaining relative enzymatic activity was above 95%.After incubation at 60 ℃ for 1 h, the remaining relative enzymatic activity was lost completely.After incubation at pH6-7.5 for 12 h ,the remaining relative enzymatic activity was 40%. DPPH and -OH free radical scavenging experiments showed that the antioxidant activity of the polysaccharide was sigificantly enhanced after the hydrolysis of pullulanase（ p 〈 0.05 ）.The study provided a new application of Dullulanase in food industry.
作者
吴永
王淑军
吕明生
房耀维
刘姝
严翠
焦豫良
WU Yong;WANG Shu-jun;LV Ming-sheng;FANG Yao-wei;LIU Shu;YAN Cui;JIAO Yu-liang(College of Marine Life Sciences and Fisheries,HuaiHai Institute of Technology,Lianyungang 222005,China;Jiangsu Key Laboratory of Marine Pharmaceutical Compounds Screening,Lianyungang 222005,China)
出处
《食品工业科技》
CAS
CSCD
北大核心
2018年第17期106-111,共6页
Science and Technology of Food Industry
基金
江苏省普通高校自然科学基金(14KJB180002)
江苏省海洋药物活性分子筛选重点实验室项目(2015HYB13)
淮海工学院研究生科研创新项目(XKYCXX2016-5)
关键词
普鲁兰酶
筛选鉴定
纯化
酶学性质
海带多糖酶解产物
抗氧化活性
pullulanase
identification
purification
enzymatic property
Laminaria japonica polysaccharide hydrolysate
antioxidant activity
