Physiological, biochemical, and cytological characteristics of a haloalkalitolerant methanotroph grown on methanol
Physiological, biochemical, and cytological characteristics of a haloalkalitolerant methanotroph grown on methanol
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DOI：
10.1023/a:1020594300166
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发表时间：
2002-09-01
期刊：
影响因子：
1.5
通讯作者：
Trotsenko, YA
中科院分区：
文献类型：
--
作者：
Eshinimaev, BT;Khmelenina, VN;Trotsenko, YA
耐盐嗜碱甲烷酵母5B能够在较高的甲醇浓度(最高1.75M)下生长。在最适pH和盐度条件下(pH 9.5和0.75%NaC l)，在0.25M甲醇(0.2h~(-1))上的最大生长速率是在甲烷上(0.1h~(-1))的两倍。最大生长速率随培养基盐度和pH的升高而增大。该菌在甲醇上生长的同时，胞质内膜的发育程度降低，细胞内出现糖原颗粒，甲醛、甲酸盐和胞外糖蛋白的积累分别为1.2 mM、8 mM和2.63g/L。糖蛋白含有23%的蛋白质和77%的碳水化合物，后者主要由葡萄糖、甘露糖和氨基糖组成。主要氨基酸为谷氨酸、天冬氨酸、甘氨酸、缬氨酸和异亮氨酸。当培养液中硝酸钾浓度增加10倍时，糖蛋白含量上升到5g/L。甲醇培养细胞蔗糖-6-磷酸合成酶、糖原合成酶和NADH脱氢酶活性均高于甲烷培养细胞。这些数据表明，分枝杆菌5B对甲醇的高耐受性是由于利用甲醛合成蔗糖、糖原和糖蛋白，以及通过呼吸链氧化过量的还原当量。
The halotolerant alkaliphilic methanotroph Methylomicrobium buryatense 5B is capable of growth at high methanol concentrations (up to 1.75 M). At optimal values of pH and salinity (pH 9.5 and 0.75% NaCl), the maximum growth rate on 0.25 M methanol (0.2 h(-1)) was twice as high as on methane (0.1 h(-1)). The maximum growth rate increased with increasing medium salinity and pH. The growth of the bacterium on methanol was accompanied by a reduction in the degree of development of intracytoplasmic membranes, the appearance of glycogen granules in cells, and the accumulation of formaldehyde, formate, and an extracellular glycoprotein at concentrations of 1.2 mM, 8 mM, and 2.63 g/l, respectively. The glycoprotein was found to contain 23% protein and 77% carbohydrates, the latter being dominated by glucose, mannose, and aminosugars. The major amino acids were glutamate, aspartate, glycine, valine, and isoleucine. The glycoprotein content rose to 5 g/l when the concentration of potassium nitrate in the medium was augmented tenfold. The activities of sucrose-6-phosphate synthase, glycogen synthase, and NADH dehydrogenase in methanol-grown cells were higher than in methane-grown cells. The data obtained suggest that the high methanol tolerance of M. buryatense 5B is due to the utilization of formaldehyde for the synthesis of sucrose, glycogen, and the glycoprotein and to the oxidation of excess reducing equivalents through the respiratory chain.