产碱性纤维素酶菌株的选育和酶合成基本特性

芽孢杆菌ｘ－６菌株经甲基磺酸乙酯（ＥＭＳ）和紫外线（ＵＶ）复合诱变,以其万古霉素抗性突变体中选育获得一突变株ＥＶ２３,所产生的纤维素酶碱性酶,且酶活力由原来的０．８４Ｕ／ｍｌ提高到３．５３Ｕ／ｍｌ,ＥＶ２３菌株基本上组成性地合成碱性羧甲基纤维素酶（ＣＭＣａｓｅ）酶合成明显表现出抗降解物阻遏的特点,以葡萄糖为碳源培养,４％浓度时酶合成水平达最高,酶合成与生长几乎同时发生,合成效率受菌体生长速率影响较     

球形芽孢杆菌的抗药标记及外源DNA的转化与表达

用亚硝基胍（NTG）对球形芽孢杆菌（Bacillussphaericus）进行化学诱变,筛选到利福平（Rif）和链霉素（Sm）二个标记菌株。抗药浓度均达100u／ml培养基。其抗药性状能够获得较好地遗传。用含溶葡球菌酶基因的质粒DNA对RifR菌株进行原生质体转化,酶基因在该抗药菌株中获得了高效表达。经摇瓶发酵试验,溶葡球菌酶的活性约为122u／ml培养液。     

紫外线诱变选育碱性蛋白酶高产菌株

本实验以枯草杆菌A4－3为出发菌株,发酵产生碱性蛋白酶,其野生型菌株产酶为2412u／ml。采用孢子热处理方法处理出发菌株孢子,得到变异株As—4,产酶2732．8u／ml。对As—4菌株进行紫外线绣变处理1min,得变异菌株AX—46,产酶为3213．8u／ml,且产酶能力稳定。     

青霉的纤维素酶抗降解物阻遏突变株的选育

从土样中筛出一株生长快,产纤维素酶较高的斜卧青霉(Penicillium decumbens114-2)。能在全纤维素(hlocellulose)双层平板上形成清晰的透明圈。摇瓶培养的滤纸酶活可达8.8mg 葡萄糖/ml.h。 114-2菌株(其纤维素酶合成可为葡萄糖所阻遏)经UV和NG诱变处理后,在含葡萄糖的全纤维素平板上筛选到多株仍能形成明显透明圈的突变株。其中JN15和JU1在含葡萄糖的全纤维素液体培养基中,在残余葡萄糖浓度为 1％左右时,滤纸酶活可分别达到7.3 和13.9mg葡萄糖ml·h。这是出发株114-2和纤维素酶高产菌株木霉EA_3-867和QM9414所不能的。在不加阻遏剂的对比试验中,两个突变株的纤维素酶产量都比较高。其中,JU1的滤纸、CMC和棉花酶活分别达到33mg葡萄糖/ml·h,234mg葡萄糖/ml·h和86mg葡萄糖/ml·24h。     

芽孢杆菌E2菌株纤维素酶形成条件的研究

芽孢杆菌E,菌株(Bacillus sp.strain E2)能在55℃下良好生长并在培养液中大量积累胞外纤维素酶(190 mu／ml培养液),所产生的纤维素酶为单一的CMCa se。对芽孢杆茁E2菌株产酶条件进行了研究． 该菌产酶的最适培养基装量为200ml/500mI三角瓶,最适起始pH为6 5,最适产酶温度为45℃,产酶高峰在培养时间8—12小时。E2菌株不能利用单一的无机氮源形成纤维素酶。酪蛋白是试验过的供E2菌株形成纤维素酶的最好氮源,其用量为3g／L。CMC—Na,纤维二糖,能作为碳源供芽孢杆菌E2菌株形成纤维素酶。高浓度的葡萄糖(8g／L)对芽孢杆菌E2菌株纤维素酶的形成有抑制作用。天然纤维素不能作为芽孢杆菌E2菌株形成纤维素酶的碳源。     

产胞外青霉素酰化酶菌株的选育

以短小杆菌（B．pumilus）B－97为出发菌株,经过连续两次紫外线诱变处理,分离得一突变株B－U－29。其酶活力为4．56U／ml,较出发菌株酶活力提高113．3％。对B－U－29菌株进行连续两次亚硝酸处理,分离得一正变稳定株B—H－29,酶活力为4．93u／ml,较出发菌株酶活力提高了20％。     

一株能分解纤维素放线茵的固态发酵研究

对一株从食草动物的粪便中分离出来的放线菌菌株（XW5）,以秸杆粉和麸皮为底物,进行固态发酵,并提取纤丝至望粗酶。采用DNS法,进行酶活测定,研究发现该菌株的固态发酵酶活为4—7u／mg。并对酶活的影响因子、pU、温度以及金属离子等的影响进行了探讨,同时发现该酶为碱性纤维素酶。     

根霉植酸酶的研究──Ⅰ.菌株的分离筛选及发酵条件研究

从21个土样和15株产酶菌株中筛选到1株产酶能力较强的菌株——根霉（Rhizopussp.）MR020。其优化培养基组成（％）：大米粉2.0,干酪素0．05,（NH4）2SO41.0,MgSO4·7H2O0.05,FeSO4·7H2O0.01,pH5.0。其振荡培养条件：培养基装最25ml／250ml三角瓶,用培养8天、浓度为1×107个／ml的孢子悬液接种1ml,于30℃,150r／min振荡培养108h产酶量最高达4000u/ml。     

碱性蛋白酶产生菌的筛选及发酵条件考查

从土壤中分离到的167株芽胞杆菌中选出一株高产、稳产碱性蛋白酶菌株A4－3（嗜碱性枯草芽胞杆菌）。该菌株最适产酶条件为（g／100ml）：蔗糖6．0;豆饼水解液10.0;Na2CO31．0;起始pH9．5。在该条件下,经37℃振荡培养48h,酶活力达2612u／ml。     

微生物法生产普鲁兰酶的研究

对产普鲁兰酶的出发菌株进行筛选和诱变,使酶活从22．10u／ml提高到了40．77u／ml,酶活提高了84．4％。随后对菌体产酶培养基进行了确定和优化,得到最佳发酵培养基,在此培养基下,菌体产酶达46．76u／ml,为原酶活的114．7％。     

Interrelationship of carbohydrate metabolism and alkaline phosphatase synthesis in Bacillus licheniformis 749/c.

Membrane-bound alkaline phosphatase of Bacillus licheniformis 749/c is derepressed by glucose in complex and chemically defined media. In the presence of lactate, pyruvate, or succinate the synthesis is repressed. The lactate repression neither affects total protein synthesis nor inhibits penicillinase synthesis. Thus, carbon sources specifically influence alkaline phosphatase synthesis. Although variations in the inorganic phosphate content of the growth media directly affect alkaline phosphatase synthesis, the intracellular inorganic and total phosphate pools appear to be unrelated to its repression or derepression. During lactate repression there is preferential incorporation of lactate molecules into glycogen, whereas no such incorporation could be detected from glucose. Net glycogen synthesis remains the same in glucose- or lactate-grown cells. It is postulated that, in phosphate-deficient growth medium, gluconeogenic metabolism regulates alkaline phosphatase synthesis.     

从万古霉素抗性突变体中筛选碱性纤维素酶高产菌株

以芽胞杆菌 Ｘ—６ 为出发菌株,经甲基磺酸乙酯（ Ｅ Ｍ Ｓ） 和紫外线（ Ｕ Ｖ） 复合诱变,选育万古霉素抗性突变体。研究结果表明,抗药性突变株碱性羧甲基纤维素酶（ Ｃ Ｍ Ｃａｓｅ） 产量提高的正变率和正变幅度明显高于非抗药性菌株。从抗性突变株中获得 Ｅ Ｖ２３ 菌株,其产酶活力比出发株 Ｘ—６ 提高３２０ ％ ,酶活力达３５３ｕ／ ｍｌ。     

Culture conditions for the production of pectinolytic enzymes by the white-rot fungus Trametes trogii on a laboratory scale

Different cultural parameters that regulate pectinolytic enzyme production in vitro by Trametes trogii were studied. When grown in a medium containing pectin, T. trogii produced extracellular polymethylgalacturonase, polygalacturonase and pectin lyase but no pectate lyase activity. No significant differences in the maximum enzyme activities measured were observed with the addition of xylan, carboxymethylcellulose or both to the medium containing pectin. The addition of glucose to that medium considerably decreases all the activities studied, and in a medium with glucose as the sole carbon source no galacturonase activity could be measured, and pectin lyase activity was at its minimum. The low synthesis of pectin lyase in cultures containing glucose suggests that this enzyme is constitutive in contrast to the polygalacturonases that were not detected. The increase in pectin concentration stimulated growth and enzyme production. The highest specific activities were attained with the greatest concentration tested (15 g/l). Casamino acids were the best nitrogen source for enzyme production. Maximum growth was measured at pH 3.3; pH values of around 4.5 stimulated enzyme production, but high pectinase activities were also detected in media with more alkaline initial pH values (6.2 for galacturonases and 6.6 for lyases), probably owing to the specific induction of particular isoforms. In the range of 23 to 28°C, good results were obtained in growth as well as in enzyme production. The addition of Tween 80 promoted growth and gave the highest yield of polymethylgalacturonase and pectin lyase (0.37 and 36.2 E.U./ml, respectively). The highest polygalacturonase activity (1.1 E.U/ml) was achieved with polyethylene glycol. Tween 20 and Triton X-100 inhibited growth and pectinase production.     

Production of alkaline protease from an alkaliphilic actinomycete

The repression of alkaline protease synthesis from alkaliphilic actinomycete was studied by using glucose, peptone, yeast extract, KH2PO4 and amino acids; tyrosine, tryptophan, lysine, and arginine. There was a critical limit of stimulation of enzyme production by these components. Crude components such as molasses, wheat flour, and wheat bran were found to be effective for growth and enzyme production. The high level of enzyme production using agro-industrial by-products is commercially significant due to cheap nature of these sources. The findings are quite attractive, as only few actinomycetes, particularly alkaliphilic ones, have so far been explored for their enzymatic potential and regulation of enzyme synthesis.     

Regulation of Secondary Metabolite Biosynthesis: Catabolite Repression of Phenoxazinone Synthase and Actinomycin Formation by Glucose

Synthesis of the secondary metabolite, actinomycin, and the enzyme, phenoxazinone synthase, involved in the biosynthesis of the antibiotic, were shown to be under severe catabolite repression by glucose. Of a variety of hexoses and carbon compounds examined, glucose, and to a lesser extent, mannose, proved to be the most repressive for enzyme synthesis. The repression by glucose was most evident before production of the antibiotic. In a chemically defined medium suitable for actinomycin production, synthesis of phenoxazinone synthase began at the time the glucose (0.1%) supply was depleted. Soon after, antibiotic synthesis was initiated. Galactose, the major carbon source for growth and antibiotic synthesis, was not utilized until the glucose was consumed. Generally, carbon compounds which supported a rapid rate of growth were most effective in producing catabolite repression.     

Elaboration of chloramphenicol acetyltransferase by cells of E. coli K-12 under conditions altering the intracellular concentration of cyclic adenosine-3',5'-monophosphate]

The influence of cAMP, ACTH and glucose on the stimulation of chloramphenicol acetyl transferase synthesis in the cells of E. coli CSH-2/R222 and E. coli WZ-78/R222. (cya855) was examined. Glucose proved to decrease the enzyme synthesis in E. coli CSH-2/R222, causing catabolite repression; 5 mM of cAMP and 1000 mug/ml ACTH overcame the latter. The enzyme synthesis in E. coli WZ-78/R222 was insensitive to the catabolite repression; as to ACTH - it failed to cause stimulation ofchloramphenicol acetyl transferase synthesis in E. coli WZ-78/R222.     

红曲AS 3．3491葡萄糖淀粉酶生物合成的调节

红曲 Monascus AS 3.978的变异株 AS 3.3491曾是葡萄糖淀粉酶的工业生产菌株。本文报告的实验结果表明该菌株的葡萄糖淀粉酶是构成酶,它的形成受降解物阻遏的调控。AS 3.3491葡萄糖淀粉酶形成的时间过程属典型的产物形成与生长呈负相关的类型,即菌丝体生长停止后酶才开始大量形成。从培养基中除去过量易利用碳源可使葡萄糖淀粉酶形成消阻遏。各种可利用碳源以低浓度分别加到洗涤的菌丝体悬浮液中都能促进葡萄糖淀粉酶的形成,其中蜜二糖和半乳糖的促进作用最甚。在限制生长的条件下,即向洗涤菌丝悬浮液连续缓慢供给低浓度葡萄糖,则在整个培养过程中,葡萄糖淀粉酶的活力稳步上升,不需要任何诱导物,并且比酶形成值达到蜜二糖培养基的水平。因此,高浓度葡萄糖阻遏葡萄糖淀粉酶形成,但低浓度葡萄糖却促进酶的形成。     

On the regulation of adenosine 3', 5'-monophosphate synthesis in bacteria. I. Effect of carbon source variation on cyclic AMP synthesis in Escherichia coli B/r.

1. The effect of carbon source variation in bacterial growth media on their growth rate, inducible enzyme and cyclic AMP synthesis was examined: an inverse relationship between the culture's growth rate and its differential rate of inducible enzyme (tryptophanase and beta-galactosidase), and cyclic AMP synthesis was found. 2. The effect of the culture's growth phase on its sensitivity or resistance to glucose catabolite repression was determined in the wild type and a catabolite insensitive mutant (ABDROI): the wild type's sensitivity to glucose repression was not affected, whereas the insensitivity of the mutant was found to be limited to its early logarithmic phase of growth. At late log, or stationary phase, the mutant was found to be sensitive to glucose repression. 3. Examination of the kinetics of glucose uptake by the mutant, using alpha-[1 4-C] methyl-glucoside showed evidence for two transport systems each with a different affinity to glucose. A low affinity transport system (apparent Km of 3.4-10-minus 5 M) which appears mostly at the early logarithmic phase of growth. A high affinity transport system (apparent Km of 1.2-10-minus 5 M) which appears mostly at the late log and stationary phases of growth. 4. The effect of the culture density variation on its sensitivity to glucose repression showed that sensitivity to glucose catabolic repression is primarily a reflection of the formation of an allosteric effector molecule between glucose and its specific transport molecule which in turn regulates the activity of the adenylate cyclase.     

Ability of a solid state fermentation technique to significantly minimize catabolic repression of α-amylase production by Bacillus licheniformis M27

Summary The production of -amylase by Bacillus licheniformis M27 in submerged fermentation was completely inhibited due to catabolic repression in medium containing 1% glucose. In contrast, the enzyme production in a solid state fermentation system was 19,550 units/ml extract even when the medium contained 15% glucose. The peak in enzyme titre was, however, shifted from 48 to 72 h. The ability of the solid state fermentation system to significantly overcome catabolic repression was not known earlier and is probably conferred by various physico-chemical factors and culture conditions specific to the system. Offprint requests to: B. K. Lonsane     

嗜碱芽孢杆菌NTT33产碱性β-甘露聚糖酶发酵条件的研究及高产菌株选育

研究了嗜碱芽孢杆菌（ａｌｋａｌｏｐｈｉｌｉｃＢａｃｌｕｓｓｐ．）ＮＴＴ３３发酵产生胞外碱性β－甘露聚糖酶的条件,其最佳碳源为１％槐豆角,最佳氮源为１％蛋白胨＋０．２％酵母膏,发酵培养３６ｈ产酶量最高（达６１．３υ／ｍＬ）。甘油,葡萄糖,甘露糖等对产酶有强的阻遏作用。该菌株经紫外诱变处理后,采用透明圈法初步筛选出在含葡萄糖和不含葡萄糖的槐豆胶培养基上同时产生透明圈的菌株,进一步测定其产酶进程曲线,最后筛选到一株（ＮＴＴ３３－ｒ６）部分消除葡萄糖代谢阻遏高产β－甘露聚糖酶的菌株,其酶活力比出发菌株提高５０％,,达到９６．３Ｕ／ｍｌ;。