Bioactive metabolites produced by Chaetomium globosum,an endophytic fungus isolated from Ginkgo biloba

A novel cytotoxic chlorinated azaphilone derivative named chaetomugilin D (1), together with three known metabolites, chaetomugilin A (2), chaetoglobosins A (3) and C (4), has been isolated by a bioassay-guided fractionation from the EtOAc extract of the cultures of Chaetomium globosum, an endophytic fungus found in the leaves of Ginkgo biloba. Structure of 1 was established by analyses of spectroscopic methods, including 2D-NMR experiments (COSY, NOESY, HMQC, and HMBC). Compounds 1–4 displayed significant growth inhibitory activity against the brine shrimp (Artemia salina) and Mucor miehei.     

Characterization of medium-chain-length polyhydroxyalkanoate biosynthesis by Pseudomonas mosselii TO7 using crude glycerol

Polyhydroxyalkanoates (PHAs) are biopolyesters produced by microorganisms that are environmentally friendly. PHAs can be used to replace traditional plastic to reduce environmental pollution in various fields. PHA production costs are high because PHA must be produced from a carbon substrate. The purpose of this study was to find the strain that can used the BDF by-product as the sole carbon source to produce high amounts of medium-chain-length PHA. Three isolates were evaluated for potential PHA production by using biodiesel-derived crude glycerol as the sole carbon source. Among them, Pseudomonas mosselii TO7 yielded high PHA content. The PHA produced from P. mosselii TO7 were medium-chain-length-PHAs. The PHA content of 48% cell dry weight in 48 h with a maximum PHA productivity of 13.16 mg PHAs L^?1 h^?1. The narrow polydispersity index value of 1.3 reflected the homogeneity of the polymer chain, which was conducive to industrial applications.     

Lipid production by yeasts grown on crude glycerol from biodiesel industry

The main carbon source used for growth by four yeast strains (Yarrowia lipolytica CCMA 0357, Y. lipolytica CCMA 0242, Wickerhamomyces anomalus CCMA 0358, and Cryptococcus humicola CCMA 0346) and their lipid production were evaluated, using different concentrations of crude and pure glycerol and glucose. Whereas crude glycerol (100?g/L) was the main carbon source used by Y. lipolytica CCMA 0357 (nearly 15?g/L consumed at 120?hr) and W. anomalus CCMA 0358 (nearly 45.10?g/L consumed at 48?hr), pure glycerol (150?g/L) was the main one used by C. humicola CCMA 0346 (nearly 130?g/L consumed). On the other hand, Y. lipolytica CCMA 0242 used glucose (100?g/L) as its main source of carbon (nearly 96.48?g/L consumed). Y. lipolytica CCMA 0357 demonstrated the highest lipid production [about 70% (wt/wt)], forming palmitic (45.73% of fatty acid composition), stearic (16.43%), palmitoleic (13.29%), linolenic (10.77%), heptadecanoic (4.07%), and linoleic (14.14%) acids. Linoleic acid, an essential fatty acid, was produced by all four yeast strains but in varying degrees, representing 70.42% of the fatty acid profile of lipids produced by C. humicola CCMA 0346.     

Microbial production of 1,3-propanediol by Klebsiella pneumoniae using crude glycerol from biodiesel preparations

1,3-Propanediol (1,3-PD) was produced by Klebsiella pneumoniae using crude glycerol obtained from biodiesel production. The 1,3-PD concentration of 51.3 g/l⁻¹ on crude glycerol from alkali-catalyzed methanolysis of soybean oil was comparable to that of 53 g/l⁻¹ on crude glycerol derived from a lipase-catalyzed process. The productivities of 1.7 g l⁻¹ h⁻¹ on crude glycerol were comparable to that of 2 g l⁻¹ h⁻¹ on pure glycerol. It could be concluded that the crude glycerol could be directly converted to 1,3-PD without any prior purification.     

High yield conversion of a crude glycerol fraction from biodiesel production to hydrogen by photofermentation

Present biodiesel manufacturing processes inevitably produce a crude glycerol side fraction. Projected future volumes of biodiesel will generate enormous quantities of glycerol of a magnitude suggesting that conversion to a fuel is the only viable route. Here we have shown that the photosynthetic bacterium Rhodopseudomonas palustris is capable of the photofermentative conversion of glycerol, both pure and a crude glycerol fraction, to hydrogen, a proposed future fuel. Relatively high yields, up to 6 moles H₂/mole glycerol (75% of theoretical, 8 moles of H₂/mole glycerol) were obtained. Even the crude glycerol fraction, at the concentrations used here, was readily converted to hydrogen with no apparent evidence of inhibition or toxicity. We show that the concentration of added nitrogen can be used to modify both rates and yields of hydrogen production with an apparent trade-off between the two. Finally, some factors are identified that might be examined in future studies in attempts to increase rates and/or yields.     

响应面法优化北豆根粗多糖的除蛋白工艺及其神经保护活性研究

为研究北豆根粗多糖的最佳除蛋白方法和工艺,探究北豆根粗多糖的神经保护活性。实验比较了酶法、Sevage法、酶-Sevage法、三氯乙酸(TCA)-正丁醇法、酶-TCA-正丁醇法除蛋白效果,筛选出了北豆根粗多糖的最佳除蛋白方法,并用响应面法对该方法进行优化。经响应面分析,以综合评分为指标,考查TCA与正丁醇体积比、北豆根粗多糖溶液与TCA-正丁醇溶液体积比和振摇时间对北豆根粗多糖TCA-正丁醇法除蛋白工艺的影响。用H_2O_2诱导PC12细胞损伤,探究了北豆根粗多糖的神经保护作用。结果表明,北豆根粗多糖的最佳除蛋白方法为TCA-正丁醇法。经响应面优化,确定最优除蛋白工艺为TCA:正丁醇=1∶10.4,北豆根粗多糖溶液:TCA-正丁醇溶液=1∶1.77,振摇时间为36.5 min。采用该工艺对北豆根多糖进行除蛋白,其蛋白清除率为73.1%,综合评分为92.1。神经保护研究结果表明,北豆根粗多糖对H_2O_2诱导的PC12细胞损伤具有明显的保护作用。本研究表明TCA-正丁醇法可以有效的除去北豆根粗多糖中的蛋白质且北豆根粗多糖具有神经保护活性。     

Optimization of glycerol feeding for clavulanic acid production by Streptomyces clavuligerus with glycerol feeding

Glycerol at 10–20 g l^–1 increased clavulanic acid production by Streptomyces clavuligerus in shake-flask culture. The biosynthesis of clavulanic acid continued for longer by feeding glycerol and production increased to 250 mg l^–1 compared with 115 mg l^–1 without feeding. In fermenter batch culture, degradation of clavulanic acid began after 72 h. With glycerol feeding in fed-batch culture, clavulanic acid production was not only increased further to about 280 mg l^–1 but also remained stable up to 130 h.     

丁酸梭杆菌发酵甘油制备1,3-丙二醇的研究

本研究采用丁酸梭芽孢杆菌(Clostridium butyricum)从甘油发酵制备1,3—丙二醇。该发酵需厌氧培养,发酵培养基为：甘油6％,葡萄糖1％,玉米浆2％,(NH4)2SO40．2％。发酵温度为34℃,pH为6．5～7。在最佳条件下,发酵50h可产1,3—丙二醇40．7g／L,甘油摩尔转化率达68％。     

Organosolv pretreatment by crude glycerol from oleochemicals industry for enzymatic hydrolysis of wheat straw

In order to defray the cost of biodiesel production, the ensuing work was to further investigate utilization of the crude glycerol (CG) from oleochemicals industry in the atmospheric autocatalytic organosolv pretreatment (AAOP) to enhance enzymatic hydrolysis.

The AAOP–CG enabled wheat straw to achieve with reasonable enzymatic hydrolysis yields, reaching 75% for the wet substrate and 63% for the dried. Lipophilic compounds from the CG formed pitch deposition on the fiber, which was responsible for low delignification (30%) and also troublesome in practical operation. Pitch deposits itself had no significant role on enzymatic hydrolysis. A striking finding of the lignin recondensation and/or lignin–carbohydrate complex helped explain why dried pretreated wheat straw had a low enzymatic hydrolysis yield. The CG was suitable for the AAOP to enhance enzymatic hydrolysis of lignocellulosic biomass. But it was advisable to remove lipophilic compounds from crude glycerol before utilization.     

Short Communication: Effect of manganese on polysaccharide production and cellular pigmentation in the fungus Aureobasidium pullulans

Manganese supplementation resulted in higher polysaccharide levels and reduced cellular pigmentation by more than 8- or 17-fold after growth for 7d of the fungus Aureobasidium pullulans ATCC 42023 on sucrose or corn syrup, respectively, as a carbon source. The melanin content of the polysaccharide elaborated by ATCC 42023 cells also decreased if MnCl2 was added to the medium. The pullulan content of the polysaccharide synthesized by ATCC 42023 on sucrose was found to increase with increasing levels of manganese, whereas it was lower during growth on corn syrup if manganese was present.     

Biohydrogen production by dark fermentation of glycerol using Enterobacter and Citrobacter Sp

Glycerol is an attractive substrate for biohydrogen production because, in theory, it can produce 3 mol of hydrogen per mol of glycerol. Moreover, glycerol is produced in substantial amounts as a byproduct of producing biodiesel, the demand for which has increased in recent years. Therefore, hydrogen production from glycerol was studied by dark fermentation using three strains of bacteria: namely, Enterobacter spH1, Enterobacter spH2, and Citrobacter freundii H3 and a mixture thereof (1:1:1). It was found that, when an initial concentration of 20 g/L of glycerol was used, all three strains and their mixture produced substantial amounts of hydrogen ranging from 2400 to 3500 mL/L, being highest for C. freundii H3 (3547 mL/L) and Enterobacter spH1 (3506 mL/L). The main nongaseous fermentation products were ethanol and acetate, albeit in different ratios. For Enterobacter spH1, Enterobacter spH2, C. freundii H3, and the mixture (1:1:1), the ethanol yields (in mol EtOH/mol glycerol consumed) were 0.96, 0.67, 0.31, and 0.66, respectively. Compared to the individual strains, the mixture (1:1:1) did not show a significantly higher hydrogen level, indicating that there was no synergistic effect. Enterobacter spH1 was selected for further investigation because of its higher yield of hydrogen and ethanol. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013     

Co-gasification of hardwood chips and crude glycerol in a pilot scale downdraft gasifier

Seeking appropriate approaches to utilize the crude glycerol produced in biodiesel production is very important for the economic viability and environmental impacts of biodiesel industry. Gasification may be one of options for addressing this issue. Co-gasification of hardwood chips blending with crude glycerol in various loading levels was undertaken in the study involving a pilot scale fixed-bed downdraft gasifier. The results indicated that crude glycerol loading levels affected the gasifier’s performance and the quality of syngas produced. When crude glycerol loading level increased, the CO, CH₄, and tar concentrations of the syngas also increased but particle concentration decreased. Though further testing is suggested, downdraft gasifiers could be run well with hardwood chips blending with liquid crude glycerol up to 20 (wt%). The syngas produced had relatively good quality for fueling internal combustion engines. This study provides a considerable way to utilize crude glycerol.     

Elevated polysaccharide production by mutants of the fungus Aureobasidium pullulans

Abstract Two mutants of the fungus Aureobasidium pullulans ATCC 42023 were isolated that exhibited elevated polysaccharide production. Both mutants were isolated using a combination of chemical mutagenesis and resistance to growth inhibitors. It was found that both mutants elaborated higher polysaccharide levels after 7 days of growth on corn syrup or sucrose, respectively, compared to ATCC 42023. The dry weights of the mutant cells were found not to differ greatly from those of the parent cells whether corn syrup or sucrose served as the carbon source. The pullulan content of the polysaccharide synthesized by the mutants or parent cells on sucrose was consistently lower than polysaccharide synthesized on corn syrup. Using corn syrup as a carbon source, the pullulan content of the polysaccharide elaborated by the parent was higher than either mutant. The inverse was found to occur with respect to pullulan content when the strains were grown on sucrose as a carbon source.     

Production and characterization of biopolyols and polyurethane foams from crude glycerol based liquefaction of soybean straw

The feasibility of using crude glycerol to liquefy soybean straw for the production of biopolyols and polyurethane (PU) foams was investigated in this study. Liquefaction conditions of 240 °C, >180 min, 3% sulfuric acid loading, and 10-15% biomass loading were preferred for the production of biopolyols with promising material properties. Biopolyols produced under preferential conditions showed hydroxyl numbers from 440 to 540 mg KOH/g, acid numbers below 5 mg KOH/g, and viscosities from 16 to 45 Pa.s. PU foams produced under preferential conditions showed densities from 0.033 to 0.037 g/cm³ and compressive strength from 148 to 227 kPa. These results suggest that crude glycerol can be used as an alternative solvent for the liquefaction of lignocellulosic biomass such as soybean straw for the production of biopolyols and PU foams. The produced biopolyols and PU foams showed material properties comparable to their analogs from petroleum solvent based liquefaction processes.     

Bioreactor studies on the endophytic fungus Entrophospora infrequens for the production of an anticancer alkaloid camptothecin

Twigs (young and old) from Nothapodytes foetida growing in the Jammu and Mahabaleshwar regions in India were used for the isolation of 52 strains of endophytic fungi and were tested for their ability to produce the anticancer alkaloid camptothecin. One of the isolates from the inner bark tissue of the N. foetida plant growing in the Jammu region of J&K state, India, was found to produce detectable quantities of camptothecin and its derivatives when grown in a semi-synthetic liquid medium. Camptothecin was identified by physicochemical analysis and further confirmed by spectroscopic studies. No camptothecin was detected in zero time cultures or in uninoculated culture broth. The maximum yield of camptothecin was 0.575 +/- 0.031 mg/100 g of dry cell mass in 96 h in shake flasks, whereas 4.96 +/- 0.73 mg/100 g of dry mass was recorded in 48 h in a bioreactor.     

Tanshinone IIA and tanshinone I production by Trichoderma atroviride D16, an endophytic fungus in Salvia miltiorrhiza

In this study the isolation of an endophytic fungus from the root of the medicinal herb Salvia miltiorrhiza Bunge is reported for the first time. The fungus produced tanshinone I and tanshinone IIA in rich mycological medium (potato dextrose broth) under shake flask and bench scale fermentation conditions. The fungus was identified as Trichoderma atroviride by its morphology and authenticated by ITS analysis (ITS1 and ITS2 regions and the intervening 5.8S rDNA region). Tanshinone I and tanshinone IIA were identified by HPLC and LC-HRMS/MS and confirmed through comparison with authentic standards. This endophytic fungus has significant scientific and industrial potential to meet the pharmaceutical demands for tanshinone I and tanshinone IIA in a cost-effective, easily accessible and reproducible way.     

Isolation and characterization of a clay-dispersing polysaccharide produced by the phytopathogenic fungus, Colletotrichum gloeosporioides

The fungus, Colletotrichum gloeosporioides, which is pathogenic to peppers produced an extracellular polysaccharide in liquid culture which possessed clay-dispersing activity. The polysaccharide could bind cationic dyes, Ruthenium Red and Alcian Blue, indicating it to be polyanionic. The polysaccharide dispersed kaolin in water and the dispersion was maintained for more than 7 days at 25 °C. Kaolin dispersion by the polysaccharide was stable from pH 3 to 10 but the addition of divalent metals at 1 mM inhibited half of the dispersion activity comparing to the control. The polysaccharide could disperse bentonite, calcium carbonate and other fine particles but did not possess emulsifying activity.     

Engineering NADH metabolism in Saccharomyces cerevisiae: formate as an electron donor for glycerol production by anaerobic, glucose-limited chemostat cultures

Anaerobic Saccharomyces cerevisiae cultures reoxidize the excess NADH formed in biosynthesis via glycerol production. This study investigates whether cometabolism of formate, a well-known NADH-generating substrate in aerobic cultures, can increase glycerol production in anaerobic S. cerevisiae cultures. In anaerobic, glucose-limited chemostat sultures (D=0.10 h(-1)) with molar formate-to-glucose ratios of 0 to 0.5, only a small fraction of the formate added to the cultures was consumed. To investigate whether incomplete formate consumption was by the unfavourable kinetics of yeast formate dehydrogenase (high k(M) for formate at low intracellular NAD(+) concentrations) strains were constructed in which the FDH1 and/or GPD2 genes, encoding formate dehydrogenase and glycerol-3-phosphate dehydrogenase, respectively, were overexpressed. The engineered strains consumed up to 70% of the formate added to the feed, thereby increasing glycerol yields to 0.3 mol mol(-1) glucose at a formate-to-glucose ratio of 0.34. In all strains tested, the molar ratio between formate consumption and additional glycerol production relative to a reference culture equalled one. While demonstrating that that format can be use to enhance glycerol yields in anaerobic S. cerevisiae cultures, This study also reveals kinetic constraints of yeast formate dehydrogenase as an NADH-generating system in yeast mediated reduction processes.     

Fermentation of glycerol by Clostridium pasteurianum--batch and continuous culture studies

The fermentation of glycerol by Clostridium pasteurianum was studied with respect to product formation as influenced by the culture conditions. In the majority of batch cultures, butanol was the main fermentation product, but a varying fraction of glycerol was also converted to 1,3-propanediol, butyric and acetic acids and ethanol. More than 60 g/l glycerol was utilized, and up to 17 g/l butanol was produced. Fed-batch cultures did not offer an advantage. When molecular nitrogen was used as a nitrogen source, the fermentation time was prolonged by a factor of 1.5. Fermentations at constant pH values between 4.5 and 7.5 did not reveal significant differences in product formation except for an increase in the ethanol content starting at pH 6.5. Chemostat cultures also yielded predominantly n-butanol, but in some fermentations, the 1,3-propanediol fraction was relatively high. The pH auxostat cultures, which were operated at a glycerol excess, contained 1,3-propanediol as the main product. As a whole, the fermentations were characterized by a certain variability in product formation under seemingly equal or slightly varied conditions. It appears that the regulation of the numerous fermentation pathways occurring in this organism is not very strict. Journal of Industrial Microbiology & Biotechnology (2001) 27, 18–26. Received 25 September 2000/ Accepted in revised form 07 April 2001