Crystallization of Glutamine Synthetase from Micrococcus glutamicus

For the defense mechanism against pathogenic bacteria in the digestive tracts of silkworm larvae reared on mulberry leaves, in vitro evidence of the formation of a true antibacterial substance was obtained. Caffeic acid (CA) derived from chlorogenic acid (ChA) was converted into caffeoquinone (CQ) by base-catalyzed oxidation in a buffer solution (pH 10.0). CQ was trapped as 6′- phenylsulfonylcaffeic acid (6′-sulfone) by the addition of benzenesulfinic acid (BSA).

The synergistc effects of amino compounds on the antibacterial activity of CQ are discussed in detail, and the probable reactions of CA with amino and thiol compounds in the alkaline solution are proposed.     

Taxonomical Study of Glutamic Acid Accumulating Bacteria,Micrococcus glutamicus nov. sp.

Taxonomical studies of a new group of strains of glutamics acid accumulating bacteria isolated in our laboratory were carried out. It was found that these strains belong to Genus Micrococcus because they are gram-positive, none-sporulating, and catalase possessing cocci. They are also pale yellowish, aerobic, and capable to reduce nitrate. Moreover, they neither utilize ammonium salt as a sole source of nitrogen in Hucker’s medium nor liquefy gelatin. From these observations, it seems that they are related to M. aurantiacus and M. epidermidis. However, our strains are different from them in the manner of acid production in milk and lactose media, and also in pigmentation, serological reactions and glutamic acid accumation.

The name of Micrococcus glutamicus nov. sp. was, therefore proposed to these strains.

The phenomenon of cell elongation and characteristics of the pigments of these strains was also investigated.     

Coimmobilized whole cells of Pseudomonas reptilivora and Micrococcus glutamicus in calcium alginate gel for the production of L-glutamic acid

A novel method of coimmobilized whole cells of Pseudomonas reptilivora and Micrococcus glutamicus, entrapped in calcium alginate beads have been used for the production of L-glutamic acid in a single stage fermentation process, using selected production medium enriched with glucose as substrate. The results obtained were compared with the L-glutamic acid production by free cells of Micrococcus glutamicus and by mixed culture of Pseudomonas reptilivora and Micrococcus glutamicus. The yield of glutamic acid obtained with mixed culture is relatively more than that the yield obtained with Micrococcus glutamicus alone. The properties of coimmobilized whole cells of Pseudomonas reptilivora and Micrococcus glutamicus in calcium alginate gel matrix have been investigated thoroughly and compared with those of free cells under most suitable conditions of fermentation.     

Regulation of lysine biosynthesis in the leucine-dependent mutant of Micrococcus glutamicus]

The role of leucine in metabolism of Micrococcus glutamicus was examined in relation to the lysis synthesis by the homoserine- and leucine-dependent strains of M. glutamicus 106 and the homoserine-dependent strain of M. glutamicus 95. In addition to the growth function, leucine produced a controlling effect on the yield of the end product. In the presence of leucine the inhibitory effect of isoleucine on the lysine yield was reduced or reversed. The end effect depended on the leucine: isoleucine ratio. The mechanism of interaction of amino acid metabolites with respect to the lysine biosynthesis in both strains is discussed.     

Optimization of medium constituents and fermentation conditions for the production of L-Glutamic acid by the coimmobilized whole cells of Micrococcus glutamicus and Pseudomonas reptilivora

Statistical experimental design was used to optimize medium constituents and the conditions of fermentation, viz., temperature, pH?and the time of fermentation. Higher yields of L-glutamic acid (37.1?kg/m³) was obtained after optimizing medium components and the conditions of fermentation. The optimal levels of medium components were: 61.5575?kg/m³ glucose, 7.3272?kg/m³ urea and 1.783?μg/dm³ biotin. The optimum productivity was achieved using optimized medium at the fermentation temperature of 33.7?°C, initial pH?7.74, and at the time of fermentation of 58.4?h.     

Effects of minerals on the production of valine byAerobacter aerogenes

A study has been made on the mineral requirements of a strain ofAerobacter aerogenes for the production of valine. It was observed that K₂HPO₄ and MgSO₄]. 7 H₂O were required at concentrations of 0.1% and 0.05% respectively while the optimum level of each of the trace elements Fe and Mo was 1 μg/ml. NaCl, KCl and trace elements like Mn, Ni, Co, Cu and Zn had an adverse effect on the production of valine. The requirements for metals except Mg for growth of the organism and valine production are different.     

A medium for commercial production of the halophilic Micrococcus nuclease.

A simple synthetic medium (glutamate-sucrose medium) was devised for production, during growth in shaken flasks, of extracellular halophilic nuclease (nuclease H) by a moderate halophile, Micrococcus varians subsp. halophilus. A simple medium consisting of 0.7% ammonium sulfate, 1.0% glucose, minerals, three vitamins, and 2 M NaCl gave good growth and excellent production of nuclease H in a jar fermentor when the pH was adjusted to 7.5 to 8.0 during cultivation.     

海藻糖生产过程中产酶发酵条件的研究

研究了产酶的培养基组分和比例以及最佳培养条件对微球菌生产麦芽寡糖基海藻糖合成酶(MTSase)和麦芽寡糖基海藻糖海藻糖水解酶(MTHase)的影响,得到最优培养基组成为：葡萄糖2．0％,酵母膏2．0％,蛋白胨1．0％,磷酸氢二钾0．1％,硫酸镁0．05％;优化后的培养条件为：以15％的接种量接种至250mL的锥形瓶中,装液量为50mL,初始pH值7．5～8．5,培养温度为30℃,摇床培养4d。经优化后菌体干重由原来的1．938g／L增加到18．5g／L,生物量几乎增长了10倍;而酶活也由原来的30．64U／g增加到206．11U／g,酶活提高了接近7倍。     

Effects of Detergents on Lysis of Micrococcus lysodeikticus by Lysozyme

The effects of detergents on the lysozyme-catalyzed hydrolysis of Micrococcus lysodeikticus cells were investigated by changing the concentration of Na-phosphate buffer and pH in the presence or absence of sucrose. Also, a parallel study of the hydrolysis of glycolchitin by lysozyme was conducted and compared to the lytic reaction. Electron microscopy was utilized to follow the changes in cell morphology during the various treatments.

None of the detergents changed turbidity of the cell suspension. However, they did affect the change in turbidity during lysis in unique ways. SDS, which is an anionic detergent, inhibited lysozyme activity and its addition to the reaction mixture caused a rapid and large decrease in the turbidity. Brij 35 and Triton X-100, which are non-ionic detergents, did not inhibit lysozyme activity, but their presence in the reaction mixture changed the rate of turbidity change. Apparently non-ionic detergents disrupt only the protoplast, while anionic detergents disrupt both the protoplast and the damaged cell. The lytic mechanism of M. lysodeikticus by lysozyme was discussed in detail.     

Effects of polyamines on the degradation of ribonucleic acids by polynucleotide phosphorylase of Micrococcus luteus.

The effects of polyamines on the breakdown of synthetic polynucleotides [poly(A), poly(C), and poly(U)] by polynucleotide phosphorylase [polyribonucleotide: orthophosphate nucleotidyltransferase, EC 2.7.7.8] from Micrococcus luteus have been studied. Although the breakdown of all the synthetic polynucleotides tested was stimulated by polyamines, the degree of stimulation by polyamines was in the order poly(C) greater than poly(A) greater than poly(U) at pH 7.5. However, the difference in degree of stimulation among polynucleotides decreased as the pH or monovalent cation concentration was increased. In the presence of heparin, an inhibitor of polynucleotide phosphorylase hydrolysis of polynucleotides, spermidine clearly stimulated the breakdown of poly(C) and poly(A), while the breakdown of poly(U) was stimulated only slightly by the addition of spermidine. Although binding of [14C]spermine to polynucleotide phosphorylase was observed by gel filtration, the amount of spermine bound to the enzyme was much less than that to RNA.     

Lysine production from hydrocarbon by Micrococcus varians 2Fa

A bacterium isolated from Assam (India) soil was found to accumulale l-lysine from hydrocarbon and was identified as a strain of Micrococcus varians. The strain is able to grow and accumulate lysine in a purely synthetic medium though supplementation of the synthetic medium with casamino acids significantly improves the yield. The yield of l-lysine under optimal conditions was found to be 2.6 g X 1(-1) of the compound isolated in crystalline form.     

Enhancement of methionine production by methionine analogue ethionine resistant mutants of Brevibacterium heali

In order to improve the methionine yield of the isolate B. heali, attempts were made to isolate mutants resistant to the methionine analogue DL-ethionine after mutagenesis with N-methyl-N′-nitro-N-nitrosoguanidine (NTG). The minimum inhibitory concentration (MIC) of ethionine for B. heali was found to be 2 mM. After mutagenesis and screening, five mutants resistant to 50 mM of ethionine were isolated. The yield of the best ethionine resistant mutant, B. heali Br EthR, was 13 mg/l of methionine medium under optimum cultivation conditions.