Laccases are multicopper oxidases with high potential for industrial applications. Several basidiomycete fungi are natural producers of this enzyme; however, the optimization of production and selection of inducers for increased productivity coupled with low costs is necessary. Lignocellulosic residues are important lignin sources and potential inducers for laccase production. Pinus taeda, a dominant source of wood‐based products, has not been investigated for this purpose yet. The aim of this study was to evaluate the production of laccase by the basidiomycete fungus Ganoderma lucidum in the presence of different inducers in submerged and solid‐state fermentation. The results of submerged fermentation in presence of 5 μM CuSO 4, 2 mM ferulic acid, 0.1 g/L P. taeda sawdust, or 0.05 g/L Kraft lignin indicated that although all the tested inducers promoted increase in laccase activity in specific periods of time, the presence of 2 mM ferulic acid resulted in the highest value of laccase activity (49 U/L). Considering the submerged fermentation, experimental design following the Plackett–Burman method showed that the concentrations of ferulic acid and P. taeda sawdust had a significant influence on the laccase activity. The highest value of 785 U/L of laccase activity on submerged fermentation was obtained on the seventh day of cultivation. Finally, solid‐state fermentation cultures in P. taeda using ferulic acid or CuSO 4 as inducers resulted in enzymatic activities of 144.62 and 149.89 U/g, respectively, confirming the potential of this approach for laccase production by G. lucidum.相似文献
The production of protease by Aspergillus tamarii was investigated in submerged fermentation using different substrates. Low basal proteolytic activity was detected on cultures with casein or gelatin as the only substrate (16–20 U/ml). The enrichment of protein medium with glucose increased the protease production up to 6 times (110 U/ml). The highest proteolytic levels were obtained in cultures supplemented with wheat bran (120 U/ml) and soybean meal (161 U/ml). One major proteolytic band with estimated molecular mass of 48 KDa was detected by SDS‐PAGE. The acetone‐precipitated enzyme was active and stable over a wide range of pH (6–9.5), and temperature (30–55 °C). The enzyme was stable for more than ten hours at temperatures up to 45 °C. The half‐lives at 50 and 55 °C were 90 min and 12 min, respectively. In presence of 5.0 mM CaCl2, the half‐life of the enzyme at 55 °C was increased to 130 min. 相似文献
A newly isolated alkalitolerant basidiomycetous fungus, identified as Crinipellis sp. RCK-1 was observed to produce laccase. The effect of different physicochemical factors on laccase production was studied. The identification of the important factors (initial pH of the medium, copper and tryptophan) with simple screening experiment involving optimization using single factor at a time strategy, was followed by application of complex response surface design for further maximizing the laccase production and was helpful in defining the effects and interactions of the physiological and nutritional factors. The statistical optimization by response surface methodology resulted in a 27.0-fold (619.9 U ml(-1)) increase in the production of laccase from Crinipellis sp. RCK-1 when compared to laccase production in unoptimized medium (23.0 U ml(-1)). The results from the response surface curve suggested that there was interaction between tryptophan and copper in a way that might resulted in positive effect on laccase production from Crinipellis sp. RCK-1. The relatively higher laccase production by Crinipellis sp. RCK-1 showed promise of offering great potential in various biotechnological applications. 相似文献
The purpose of this study was to isolate lignin-degrading bacteria from buffalo rumen and to explore their interactions further. Using lignin as the carbon source, three bacteria, B-04 (Ochrobactrum pseudintermedium), B-11 (Klebsiella pneumoniae), and B-45 (Bacillus sonorensis), which have shown lignin degradation potential, were successfully isolated and identified from the rumen fluid of buffalo by colony morphology, 16S ribosomal RNA gene sequencing, and biochemical and physiological analyses. The degradation rates of lignin were determined, and the maximum values were 4.86%, 11.1%, and 7.68% for B-04, B-11, and B-45, respectively. The maximum laccase activities were 0.65, 0.93, and 1.15 U/ml, while the maximum lignin peroxidase activities were 5.72, 8.29, and 18.69 U/ml, respectively. Pairwise interaction studies showed inhibitory interaction between B-04 and B-45, inhibitory interaction between B-04 and B-11, and symbiotic interaction between B-11 and B-45. This is the first report on the lignin degradation ability of bacteria isolated from the buffalo's rumen, which provides a new understanding for revealing the mechanism of roughage tolerance of buffalo. 相似文献
Lipase production by the mutant strain Rhizopus sp. BTNT-2 was optimized in submerged fermentation. Different chemical and physical parameters such as carbon sources, nitrogen sources, oils, inoculum level, pH, incubation time, incubation temperature and aeration have been extensively studied to increase lipase productivity. Potato starch (1.25% w/v) as a carbon source, corn steep liquor (1.5% w/v) as a nitrogen source and olive oil (0.5% v/v) as lipid source were found to be optimal for lipase production. The optimal levels of other parameters are 4 ml of inoculum (2.6x10(8) spores/ml), initial pH of 5.5, incubation time of 48 hours, incubation temperature of 28 degrees C and aeration rate of 120 rpm. With the optimized parameters, the highest production of lipase was 59.2 U/ml while an yield of only 28.7 U/ml was obtained before optimization resulting in 206% increase in the productivity. 相似文献
A facile route has been discovered for the synthesis of polypeptides containing adamantane moieties in the side chain, poly(Nδ‐adamantyl‐l ‐glutamine) P1 and poly(Nγ‐adamantyl‐l ‐asparagine) P2 , through polycondensation of an N‐phenoxycarbonyl derivative of the corresponding Nδ‐adamantyl‐l ‐glutamine 1 and Nγ‐adamantyl‐l ‐asparagine 2 , respectively, along with the elimination of phenol and CO2. The urethane derivatives are readily synthesized by the N‐carbamylation of tetrabutylammonium salts of α‐amino acids with diphenyl carbonate. Polycondensation of the urethane derivative proceeds smoothly upon heating to 60 °C in N,N‐dimethylacetamide using n‐butylamine (n‐BuNH2) as an initiator. Size exclusion chromatography, 1H NMR spectra, and matrix‐assisted laser desorption/ionization time‐of flight mass spectrometry analyses reveal that polycondensation of 1 with n‐BuNH2 yields a well‐defined polypeptide in terms of molecular weight and terminal structure. On the other hand, polycondensation of 2 affords poor molecular weight control and leads to the formation of oligopeptides. Furthermore, using amine‐terminated poly(ethylene‐glycol) in place of n‐BuNH2 yields a diblock copolymer composed of polyether and polypeptide segments bearing an adamantane moiety through polycondensation of the urethane derivative.
Spent mushroom substrate (SMS), a major byproduct of the mushroom industry, is a lignocellulosic biomass, which contains approximately 57–74.3% of holocellulose fraction. This study was aimed at utilizing SMS of Pleurotus florida for recovery of lignocellulolytic enzymes and sugars and also as a substrate for production of cellulolytic enzymes using different isolates of Trichoderma and Aspergillus under solid-state fermentation (SSF). SMS of P. florida extracts contained significant amounts of laccase (3,015.8 ± 29.5 U/g SMS) and xylanase (1,187.9 ± 12 U/g SMS) activity. Crystallinity pattern and chemical changes in SMS revealed that SMS had a lower crystallinity index (34.2%) as compared with the raw biomass (37.8%), which, in turn, helps in enhancing the accessibility of cellulolytic enzymes to holocellulose. Among the isolates, Trichoderma longibrachiatum A-01 showed maximum activity of endoglucanase (220.4 ± 5.9 U/mg), exoglucanase (78.5 ± 3.2 U/mg) and xylanase (1,550.4 ± 11.6 U/mg) while Aspergillus aculeatus C-08 showed maximum activity of cellobiase (113.9 ± 3.9 U/mg). Extraction with sodium citrate buffer (pH 4.8) showed maximum cellulolytic enzyme activity as compared with other solvents tested. Partial purification of endoglucanase, exoglucanase, xylanase, and cellobiase resulted in 56.3% (1,112.5 U/mg), 48.4% (212.5 U/mg), 44% (4,492.3 U/mg), and 62% (705.0 U/mg) yield with an increase by 5.2-, 4.5-, 4.1-, and 5.0-fold as compared with crude extract. The results reveal that SMS from P. florida could be a potential and cost-effective substrate for production of cellulolytic enzymes from T. longibrachiatum A-01 and A. aculeatus C-08. 相似文献
Changes in cultural parameters and the production of some extracellular enzymes during growth and autolysis of the white-rot fugus Pycnoporus cinnabarinus have been studied. At the end of the autolytic period (52 days of incubation) the degree of autolysis was greater than 50%. The laccase activity reached its highest value during the growth period, when the level of the carbon source in the medium was still comparatively high. When the fungus was cultivated in the presence of kraft lignin (Indulin AT) 0.05% (w/v), the activity of laccase was 3 times higher than when grown in the absence of lignin. The presence of lignin did not affect the activities of 1,3-β-glucanase, exoxylanase and proteases. 相似文献
Summary A position-specifically labelled phosphatidylcholine is the substrate for the selective determination of Phospholipase A2 in serum, ascites and tissue samples. Optimal reaction conditions and simplifications of handling are discussed.A control group of human serum samples ranged up to 2.1 U/l. The maximum serum activity in samples of patients with acute pancreatitis was 126 U/l. In human ascites activities up to 380 U/l were measured. The method described here turned out to be a practicable instrument for the determination of phospholipase A2 activity using only commercially available reagents.Abbreviation PlA2
Phospholipase A2相似文献
Laccases are multicopper oxidases (E.C. 1.10.3.2) that catalyze the oxidation of many phenolic compounds. In this study, a novel laccase, Stlac4, from Setosphaeria turcica was cloned and expressed in Escherichia coli by insertion into the pET‐30a expression plasmid. The recombinant laccase was purified and visualized on SDS–PAGE as a single band with an apparent molecular weight of 71.5 KDa, and confirmed by Western blot. The maximum activity of the purified laccase was 127.78 U · mg?1, the optimum temperature and pH value were 60 °C and 4.0 respectively, measured by oxidation of 2,2′‐Azinobis‐(3‐ethylbenzthiazoline‐6‐sulphonate) (ABTS). Purified laccase activity under different metal ions and an inhibitor were tested, revealing that laccase activity increased by approximately 434.8% with Fe3+, and 217.4% with Cu2+ at 10 mmol · L?1 concentrations, Mn2+ increased the laccase activity only at 5 mmol · L?1, while Na+ increased activity at 1 mmol · L?1 but inhibited activity at 5 and 10 mmol · L?1. SDS increased laccase activity at 1 mmol · L?1, and inhibited activity at 5 and 10 mmol · L?1. 相似文献