Objective:To investigate the effects of different ecological factors on growth and development of algae in biological crust in eastern margin desert region of Qingzang plateau and find out the best cultivating conditions.Methods:Samples were obtained from every sampling areas,loaded in abacterial pockets and stored at-20 ℃.Different concentrations of soil suspension liquid were prepared and coated homogeneously on sterile BG11 solid cultural medium at light/dark=16 h/18 h and 25 ℃ for one month.Chose single algae and inoculated in BG11 liquid nutrient medium to pure culture,and compared the number of algae in different pH,Na+ concentration and Mg2+ concentration.Results:In the neutral condition,the absorbency increased as culture time expanding;the absorbency of species 1 reached the maximum and began to reduce on the 13th day,at pH=5;the maximal absorbency attained on the 15th day,at pH=9 or pH=11;there is dose dependent between the growth process of species 1 and Na+ concentration and Mg2+ concentration.Conclusion:The desert algae has some resistance to alkali,however,strong basicity would affect the growth of algae.It appears to be inverse relationship between algae growth and salinity.

纤维素酶是一类能水解纤维素生成葡萄糖或纤维二糖的酶.目前,已有许多关于各种细菌、真菌、植物、动物生产纤维素酶的报道,但这些不同微生物来源的纤维素酶在生物物理、生物化学性质方面存在着相当大的差异.因此,本文对纤维素酶的分子生物学领域的最新研究成果进行了综述,以便于研究的开展.

为了得到产酶性能好且稳定的菌株,利用CMC平板初筛和摇瓶发酵复筛,从采自不同地区的样品中筛出5株产酶较高的菌株。采用液体发酵方法对其中产酶最好的菌株A6产酶条件进行研究。结果表明,该菌株最适产酶温度为32℃,初始pH值为5.5,接种量为5%,培养时间为4d,微晶纤维素与麸皮配比为7:3,氮源为复合氮源。