代谢途径抑制剂及前体对海洋红树林内生真菌No.1403产抗肿瘤化合物1403C的影响

采用酶抑制剂法和前体喂养试验法初步研究了结构新颖的活性蒽醌化合物1403C的合成途径.研究表明,甲羟戊酸合成途径的关键酶抑制剂邻氨基苯甲酸、柠檬酸三钠对单位菌体1403C产量影响比较小;莽草酸途径关键酶氨基苯甲酸合成酶的抑制剂三甲胺在低浓度时(3、6 mmol/L)对单位菌体1403C产量没有影响,而高浓度(12 mmol/L)时由于较大程度改变发酵液pH而降低了单位菌体1403C产量;莽草酸途径中间产物莽草酸的添加对单位菌体1403C产量没有明显的影响;添加聚酮合成途径聚酮合酶的专一性抑制剂碘乙酰胺对1403C的合成产生强烈的抑制,抑制程度达94.2%;添加丙二酸对1403C的合成有较大的促进作用,单位菌体1403C产量最大增加了59.2%.乙酸钠和丙二酸混合比例为1∶ 4时对单位菌体1403C产量具有最大促进作用,最大提高量为102.7%.由此推断Halorosellinia sp.(No.1403)可能通过聚酮途径合成1403C.     

海洋真菌Xylaria sp.(No.2508)生产xyloketal B的发酵优化

对海洋真菌Xylariasp．（No．2508）生产xyloketa]B的摇瓶发酵过程进行了初步优化。结果表明,Xylariasp．（No．2508）在培养120h时xyloketalB产量最高,当培养168h后菌体进入衰亡期且xyloketalB迅速降解,因此Xylariasp．（No．2508）生产xyloketalB的最适发酵周期为120h;Xylariasp．（No．2508）合成xyloketalB的过程及用乙酸乙酯萃取xyloketalB的过程对pH非常敏感,其中最适xyloketalB生产的发酵液初始pH为5．7,利用乙酸乙酯萃取xyloketalB时的发酵液最适pH为3。0;最适接种量为10％（v／v）;接种前发酵液中加入10g／L的大孔树脂XAD-16可以降低某些代谢产物对xyloketalB合成的抑制作用,从而使产量提高2倍左右,而菌体进入稳定期以后加入大孔树脂XAD-16对产物产量没有影响。     

Fermentation optimization of xyloketal B produced by marine fungus Xylaria sp.(No.2508)

对海洋真菌Xylaria sp.(No.2508)生产xyloketal B的摇瓶发酵过程进行了初步优化.结果表明,Xylaria sp.(No.2508)在培养120 h时xyloketal B产量最高,当培养168 h后菌体进入衰亡期且xyloketal B迅速降解,因此Xylaria sp.(No.2508)生产xyloketal B的最适发酵周期为120h;Xylaria sp.(No.2508)合成xyloketal B的过程及用乙酸乙酯萃取xyloketal B的过程对pH非常敏感,其中最适xyloketal B生产的发酵液初始pH为5.7,利用乙酸乙酯萃取xyloketal B时的发酵液最适pH为3.0;最适接种量为10％(v/v);接种前发酵液中加入10 g/L的大孔树脂XAD-16可以降低某些代谢产物对xyloketal B合成的抑制作用,从而使产量提高2倍左右,而菌体进入稳定期以后加入大孔树脂XAD-16对产物产量没有影响.     

外源有机酸对红树林内生真菌发酵生产1403C的影响

本文主要研究了外源有机酸对红树林内生真菌No.1403发酵生产1403C的影响,并且分别在摇瓶和5 L反应器进行柠檬酸(钠)的间歇性补加实验。研究发现在新培养基条件下添加丙二酸前体对1403C产量无促进作用。摇瓶发酵前期添加的柠檬酸对1403C合成代谢有轻微抑制效应,中后期补加的柠檬酸很可能被用于维持菌体的初级代谢。而反应器发酵的1403C产量比对照产量提高8.6%,达到0.81 g/L;碳饥饿时期,在pH7.0且菌体稳定存在条件下,添加外源柠檬酸可促进1403C的合成。     

海洋真菌Diaporthe sp.产真菌环氧二烯发酵条件的优化

从海洋木栖真菌HLY-2分离得到的真菌环氧二烯(Mycoepoxydiene)是新发现的高抗肿瘤活性化合物。通过正交设计,改良普通半海水PD培养基的配方,比较固体和液体两种发酵方法,得到了使该化合物产量大幅提高的最佳培养条件:在固体发酵条件下土豆250g/L,海水300mL/L,葡萄糖30g/L,乳糖50g/L,磷酸二氢钾0·65mmol/L,硫酸铵1g/L,产量高达543mg/L,比普通的PD培养基提高了43倍,也比液体发酵的最高产量提高了近15倍。同时还对固体发酵和液体发酵造成的产量差异进行了分析。并检验了发酵产物的抗肿瘤活性。     

青蒿内生真菌Alternaria sp.(PQH12)提取物体外细胞毒活性及抗氧化活性的研究

本文分别采用环己烷、正丁醇、乙酸乙酯、丙酮、甲醇5种极性不同的溶剂分别提取青蒿内生真菌Alternaria sp.(PQH12)的菌丝体。采用MTT法分别测定不同极性溶剂提取物对3种肿瘤细胞株(HL-60、MCF-7和COLO205)的生长抑制率,采用DPPH自由基清除法和超氧阴离子O-·2清除法评价了青蒿内生真菌Alternaria sp.(PQH12)不同极性溶剂提取物的抗氧化活性。结果显示,正丁醇和乙酸乙酯提取物均表现出对肿瘤细胞生长的抑制作用;浓度为20μg/mL时,正丁醇提取物对HL-60细胞的生长抑制率为80.56%,乙酸乙酯提物对MCF-7和COLO205细胞的生长抑制率分别为54.47%和83.09%;在两种抗氧化活性评价体系中,甲醇提取物的抗氧化活性均明显优于其他溶剂的提取物,其IC50值分别为0.20 mg/mL(DPPH)和0.19 mg/mL(O-·2)。该结果表明,青蒿内生真菌Alternaria sp.(PQH12)具有较好的细胞毒和抗氧化潜力,具有一定的开发利用价值,可以作为进一步实验研究的对象。     

海洋细菌Cellulophaga sp.QY201产内切纤维素酶发酵条件的研究

本文对海洋细菌Cellulophaga sp.QY201产内切纤维素酶的发酵条件进行了研究.研究结果表明,该菌株最佳产酶的液体培养基组成为(w/v):CMCNa 0.5%,CaSein 0.3%,NaCl 3%,MgSO4·7H2O 0.3%,Na2HPO4 0.15%,NaH2PO4 0.1%,pH=7.0;最佳培养条件为:500mL三角瓶装液150mL,温度为28℃,转速为100 r/min,发酵时间为36h.优化后发酵上清液的内切纤维素酶活力可达到7.85 U/mL,比优化前提高了2.5倍.该菌株产酶发酵条件的研究,为内切纤维素酶的大规模制备及应用奠定了基础.     

产腈水合酶菌Nocardia sp.HD9611的发酵条件优化的研究

探讨了种龄、接种量、搅拌转速、pH及补料等因素对Nocardia sp.HD9611产腈水合酶的影响.结果表明,最佳种龄为20h;接种量对酶活的提高没有明显影响,但7.5%时最佳;当搅拌转速低于400r/min时,溶解氧将成为细胞生长的限制因子;发酵过程中pH调节对细胞量及酶活的提高有积极的作用;补料对细胞密度及酶的产生有积极影响,总糖为80g/L时,细胞量31.88g/L,提高了120.8%,酶活为7100U,提高了107.6%.此研究为制定最佳控制策略提供了参考.     

红树林细菌G1产抗菌活性物质发酵条件的优化

目的:对一株从广西山口红树林保护区筛选得到的具有广谱抗菌活性的红树林细菌G1进行发酵条件的研究.方法:采用单因素实验法对G1产抗菌活性物质的发酵培养基及培养条件进行研究.结果:确定了红树林细菌G1的最佳发酵培养基为:蔗糖2.0％、酵母粉1.5％、NaCl1％.最佳发酵培养条件为:装液量40％、接种量5％、发酵时间84h、初始pH值8.0,优化后G1发酵液的抗菌活性提高了2倍.结论:初步确定了G1发酵的条件,为工业化生产抗菌活性物质提供了理论依据.     

一株产紫杉醇内生真菌液体发酵工艺的优化

紫杉醇是一种高效、低毒、广谱的天然抗癌药物,可以有效地治疗乳腺癌、子宫癌等。近年来的研究发现,从植物内生真菌中发酵生产紫杉醇被证明是解决药源问题的有效途径。从分离到的420株内生真菌中筛选到一株产紫杉醇的内生真菌XC1-07为实验材料进行发酵条件的初步优化。结果表明：最适碳源、氮源分别是麦芽糖和NH4NO3;在含10g/L NH4NO3、90g/L麦芽糖、1.0g/L MgSO4、pH6的优化培养基中培养13d,紫杉醇的产量为1,124.34μg/L。为目前报道的植物内生真菌发酵生产紫杉醇最高的产量。     

红树内生海洋细菌CIII-1发酵条件初步研究

摇瓶法测定结果表明,用7号培养基,初始pH 7.5,装液量1/10摇瓶体积,转速150 r/min,温度25℃下培养96 h,菌株分泌产生抗番茄青枯病细菌的物质最多,抑菌圈直径最大,为红树植物内生海洋细菌CIII-1菌株产抗植物青枯病菌物质的最佳培养条件。并发现该菌株产生的抗菌物质对西瓜枯萎病菌、香蕉枯萎病菌等植物病原真菌也有较强的拮抗作用。     

Astin C Production by the Endophytic Fungus Cyanodermella asteris in Planktonic and Immobilized Culture Conditions

The fungal endophyte Cyanodermella asteris (C. asteris) has been recently isolated from the medicinal plant Aster tataricus (A. tataricus). This fungus produces astin C, a cyclic pentapeptide with anticancer and anti‐inflammatory properties. The production of this secondary metabolite is compared in immobilized and planktonic conditions. For immobilized cultures, a stainless steel packing immersed in the culture broth is used as a support. In these conditions, the fungus exclusively grows on the packing, which provides a considerable advantage for astin C recovery and purification. C. asteris metabolism is different according to the culture conditions in terms of substrate consumption rate, cell growth, and astin C production. Immobilized‐cell cultures yield a 30% increase of astin C production, associated with a 39% increase in biomass. The inoculum type as spores rather than hyphae, and a pre‐inoculation washing procedure with sodium hydroxide, turns out to be beneficial both for astin C production and fungus development onto the support. Finally, the influence of culture parameters such as pH and medium composition on astin C production is evaluated. With optimized culture conditions, astin C yield is further improved reaching a five times higher final specific yield compared to the value reported with astin C extraction from A. tataricus (0.89 mg g^?1 and 0.16 mg g^?1 respectively).     

Improved production of the anticancer compound 1403C by glucose pulse feeding of marine Halorosellinia sp. (No. 1403) in submerged culture

Effects of different pulse fed-batch methods on production of the anti-cancer compound 1403C by marine mangrove endophytic fungus Halorosellinia sp. (No. 1403) in a 5-L bioreactor were investigated. Since high glucose concentrations improved mycelial growth but inhibited 1403C production, the cultures were pulse fed with glucose solutions to keep the residual glucose lower than 4 g/L but higher than 0.5 g/L during rapid growth phase (0-50 h). In this way, a maximum dry biomass, 1403C production and yield coefficient (Y1403C/X) of up to 4.5 g/L, 2.64 g/L and 0.59 g/g dry cell weight, respectively were achieved. These values are 22.7%, 98.0% and 61.4%, respectively higher than those obtained with batch cultures. This strategy is valuable for fermentation scale-up of Halorosellinia sp. (No. 1403) for 1403C production, and might also be applicable to other marine fungi cultures.     

红树林内源生真菌Sporothrix sp.#4335代谢产物的研究

Diaporthin(1),松胞素4(2)是由一株红树林共生真菌Sporothrix sp.#4335中分离的两个化合物,其结构通过光谱分析确定。并首次对化合物1进行了抗人的肝癌细胞hepG 2及抑制人的DNA拓扑异构酶I(hTopoⅠ)的活性测试,结果显示,化合物1有一定的抗肿瘤活性(IC50为23μg/mL),及很强地抑制拓扑异构酶I的活性。     

鞘氨醇单胞菌TP-3合成新型生物聚合物Ss的发酵条件优化

鞘氨醇单胞菌(Sphingomonas sp.)TP-3能合成一种具有增稠性、假塑性、成凝胶特性和乳化性能的新型生物聚合物Ss。运用单因素实验和均匀设计法对菌株TP-3合成聚合物Ss的发酵条件进行优化, 实验结果表明, 培养基组成为葡萄糖41.2 g/L, 豆饼粉2.0 g/L, NaCl 0.85 g/L, K2HPO4 1.46 g/L, MgSO4 0.12 g/L, MnCl2 0.0075 g/L, FeSO4 0.002 g/L, 初始pH为7.0, 在27°C, 180 r/min的条件下摇床培养60 h, 聚合物Ss的产量达到21.5 g/L。该聚合物生产成本低, 在油田开发中极具应用前景。     

Flocculant Production by Paecilomyces sp. Taxonomic Studies and Culture Conditions for Production

Screening of microorganisms producing a new kind of flocculating substance was carried out. A fungus that produced a large amount of a strong microbial cell flocculant was isolated from soil. The fungus was classified as a Paecilomyces species. The substance produced showed very interesting and unique flocculation characteristics. It could efficiently flocculate all tested suspended solids in aqueous solution, and flocculation was practically not affected by ionic strength, pH or temperature.

The influence of components of the culture medium upon the flocculant production by Paecilomyces sp. 1-1 was studied. Addition of hydrolysates of casein such as casamino acid and polypeptone stimulated the production of the flocculant. A high concentration of calcium ions also significantly increased the mycelial growth and the production of the flocculant. Under the optimum cultural conditions, a 500-fold dilution of the culture filtrate could efficiently flocculate and sediment E. coli cells.     

Chaetochromones A – C,Three New Polyketides from Mangrove Plant Derived Endophytic Fungus Phomopsis sp. SCSIO 41006

Three new polyketides, chaetochromones A – C ( 1  –  3 ), together with a chromone ( 4 ), were isolated from the ethyl acetate extract of mangrove‐derived fungus Phomopsis sp. SCSIO 41006. Their structures were elucidated by means of spectroscopic techniques (UV, IR, MS, 1D‐ and 2D‐NMR). The absolute configurations of the new compounds were established by CD data.     

海洋Cellulophaga sp.QY201产生L-卡拉胶酶的发酵条件优化

目的:通过发酵条件优化,提高海洋Cellulophaga sp.QY201的L-卡拉胶酶产量.方法:采用正交试验分别时发酵条件、培养基配方进行优化.结果:该茵株最适培养基配方为(w/v):3%NaCl、0.5%MgSO4·7H2O、0.02%CaCl2、0.01%KCl、0.002%FeSO4、0.25%CaSein、0.15%Na2HPO4,0.2%NaNO3、0.25%L-卡拉胶.最佳培养条件为:培养基体积为70ml/250ml三角瓶,接种量为1%,25℃,90 r/min培养36 h.优化后酶活最高可迭2.64 U/ml,较优化前提高了22倍.结论:QY201最佳发酵条件的建立,为L-卡拉胶酶的大规模生产创造了条件.