Use of steam explosion liquor from sugar cane bagasse for lignin peroxidase production by Phanerochaete chrysosporium

The possibility of using two by-products of the sugar cane industry, molasses and bagasse steam explosion liquor (SEL), for lignin peroxidase (LiP) production by Phanerochaete chrysosporium was investigated. For comparison, the fungus was initially cultivated in synthetic media containing either glucose, sucrose, xylose, or xylan as sole carbon sources. The effect of veratryl alcohol (VA) was also investigated in relation to the enzyme activity levels. Results showed that sucrose was not metabolized by this fungus, which precluded the use of molasses as a carbon source. Glucose, xylose, and xylan promoted equivalent cell growth. Enzyme levels in the absence of VA were lower than 28 UI/L and in the presence of VA reached 109 IU/L with glucose and 85 IU/L with xylose or xylan. SEL was adequate for P. chrysosporium LiP production as LiP activity reached 90 IU/L. When VA was added to this medium, enzyme concentration increased to 155 IU/L.     

Lignin peroxidase and protease production by Streptomyces viridosporus T7A in the presence of calcium carbonate

Streptomyces are good producers of enzymes of industrial interest, such as lignin peroxidase (LiP) and proteases. To optimize production of these enzymes by Streptomyces viridosporus T7A, two parameters were evaluated: carbon sources and calcium carbonate. Shake-flask fermentations were performed using culture media, with and without CaCO₃, contained yeast extract, mineral salts and either glucose, lactose, galactose, or corn oil. In the absence of calcium carbonate, the maximum values for LiP and protease activities occurred during the idiophase with LiP activity being favored by glucose, corn oil, and galactose, and protease activity being favored only by corn oil. Calcium carbonate affected the cell morphology by reducing the size of the pellets. Moreover, in the presence of the salt, LiP production was growth-associated in all media but the glucose medium. Higher enzyme levels were observed when galactose and glucose were used as carbon sources. Protease activity was repressed by both glucose and galactose, whereas corn oil was the best carbon source for the enzyme production. Calcium carbonate increased LiP production by up to 2.6-fold. Such improvement was not observed for protease production, suggesting a selective effect of CaCO₃ on LiP activity.     

Lignin peroxidase production by Streptomyces viridosporus T7A

Lignin peroxidase (LiP) production cost should be reduced to justify its use in the control of environmental pollution. In this work, we studied the enzyme production by Streptomyces viridosporus T7A using glucose or corn oil as a carbon source having 0.65% yeast extract as a nitrogen source. Enzyme activity, observed using either 0.65% glucose or corn oil at 0.1, 0.5, and 1.0% concentration, was 300, 150, 300, and 200 U/L, respectively. Although higher enzyme activity was obtained in both media containing 0.65% glucose and 0.5% corn oil, the use of corn oil resulted in a better LiP stability. When combined carbon sources were used, higher values of enzyme activity (360, 350, and 225 U/L) were observed in media with 0.65% glucose and supplemented with 0.1, 0.5, and 1.0% corn oil, respectively. Although the presence of both glucose and 0.5% corn oil is favorable for LiP production, satisfactory results in terms of enzyme production and stability could be also observed using 0.5% corn oil as a sole carbon source, which may lead to reduced production costs of the LiP enzyme.     

Cotton Stalk Pretreatment Using <Emphasis Type="Italic">Daedalea flavida</Emphasis>, <Emphasis Type="Italic">Phlebia radiata</Emphasis>, and <Emphasis Type="Italic">Flavodon flavus</Emphasis>: Lignin Degradation,Cellulose Recovery,and Enzymatic Saccharification

Lignocellulolytic enzyme activities of selective fungi Daedalea flavida MTCC 145 (DF-2), Phlebia radiata MTCC 2791 (PR), and non-selective fungus Flavodon flavus MTCC 168 (FF) were studied for pretreatment of cotton stalks. Simultaneous productions of high LiP and laccase activities by DF-2 during early phase of growth were effective for lignin degradation 27.83 ± 1.25 % (w/w of lignin) in 20-day pretreatment. Production of high MnP activity without laccase in the early growth phase of PR was ineffective and delayed lignin degradation 24.93 ± 1.53 % in 25 days due to laccase production at later phase. With no LiP activity, low activities of MnP and laccase by FF yielded poor lignin degradation 15.09 ± 0.6 % in 20 days. Xylanase was predominant cellulolytic enzyme produced by DF-2, resulting hemicellulose as main carbon and energy source with 83 % of cellulose recovery after 40 days of pretreatment. The glucose yield improved more than two fold from 20-day DF-2 pretreated cotton stalks after enzymatic saccharification.     

Elicitation of lignin peroxidase inStreptomyces lividans

Using a novel starch-based medium (DJMM) which elicits high expression of lignin peroxidase (ALiP-P3) fromStreptomyces viridosporus T7A, significant levels of ALiP-P3 (between 1135 and 1784 nmol/g cell-min) were excreted byS. lividans TK23, TK24, and TK64 with the supernatants capable of degrading dichlorophenol (these strains were previously reported to produce low levels of LiP). TheS. lividans wildtype strains produced 1/9 to 1/6 the cell-specific LiP activity previously detected inS. viridosporus T7A cultures grown in the same starch-based medium; however, by using DJMM to increase the cell density, the volumetric activity of wild-typeS. lividans TK23, TK24, and TK64 strains was increased 11 to 20-fold compared to cultivations in a yeast-extract-based medium. Consequently, this increase of LiP production allows the direct analysis of LiP activity in the supernatants of these strains without the need for enzyme concentration through ultrafiltration. Immunoblot analysis verified that a single 56.5 kDa band, secreted by all three strains, was extremely similar in size and immunologic reactivity to the 59.5 kDa ALiP-P3 isoform of S.viridosporus T7A. In addition, Western blot analysis was used to show that a previously cloned 4.1 kb chromosomal fragment ofS. viridosporus T7A DNA did not contain the ALiP-P3 structural genes.     

Influence of media nutrients on synthesis of lignin peroxidase from Aspergillus sp

The effect of carbon and nitrogen sources, lignocellulosic substrates, and metal ions on lignin peroxidase (LiP) activity of Aspergillus sp., which was isolated from a mangrove area, was studied. Glucose (1%) was found to be the best carbon source. Among the various lignocellulosic substrates used, coir pith at 3% concentration increased LiP activity twofold on the second day of incubation. Peptone and KNO₃ completely inhibited the enzyme synthesis while (NH₄)₂SO₄ at 12.5 mM produced maximum activity. Since seawater contained all the requisite metal ions, any added ions had a negative effect on activity. Cu²⁺ had the most inhibiting effect while K⁺ the least. When all the optimized conditions were provided, in nitrogen- and carbon-sufficient medium, a maximum LiP activity of 345 U/mL was obtained on the second day of incubation.     

Decolorization of olive mill waste-waters by free and immobilizedPhanerochaete chrysosporium cultures

This paper describes the decolorization and chemical oxygen demand (COD) removal of olive mill waste-waters (OMW) byPhanerochaete chrysosporium grown in agitated submerged cultures. WhenP. chrysosporium was cultivated in the form of pellet, no decolorization of crude OMW was observed. Decolorization occured only after removing by ultrafiltration, the high-mol-wt (HM) polyphenolic fraction (> 60 kDa). The use of high lignin peroxidase (LiP) producing medium yielded the highest levels of OMW decolorization and COD removal. In this case, extensive depolymerization and subsequent accumulation of phenolics with intermediates molecular weight were observed. Furthermore, increasing the concentration of the HM fraction decreased the color and COD removals. The decolorizing activity was lost when the concentration of the HM fraction reached 25% (v/v). Consequently, LiP activity was found to be completely inhibited in the presence of HM fraction, but not with the low-mol-wt (LM) polyphenolic fraction (<8 kDa). The use ofP. chrysosporium immobilized on polyurethane foam resulted in efficient decolorization of crude OMW. Moreover, the addition of an induction medium was shown to perform several repeated batch cultures for OMW decolorization and COD removal.     

直链醇对反胶束体系中木素过氧化物酶催化活性的影响

根据研究发现, 在有醇作助表面活性剂的CTAB反胶束中木素过氧化物酶(LiP)不能表现活力, 而在水介质中CTAB对LiP的催化活性影响又不是很大. 为了揭示其中醇的影响, 本工作就不同碳链长度的醇对LiP酶催化性能的影响进行了研究. 由于CTAB反胶束体系中醇浓度较高, 且碳原子数大于4的直链醇在水中的溶解度又很小, 为此采用了LiP可在其中显示催化活性的CTAB正胶束、AOT反胶束和Brij30反胶束作介质, 通过研究这些介质中不同链长的醇对LiP催化活力的影响, 来探讨CTAB反胶束中木素过氧化物酶(LiP)不能表现活力的原因. 结果表明, 不管表面活性剂聚集体的结构、电性质及反胶束大小如何, 只要醇的浓度超过500 mmol•L^－1 (丁醇≥1200 mmol•L^－1), LiP在上述原本可显示活力的介质中均无催化活性. 据此推测CTAB反胶束中木素过氧化物酶(LiP)不能表现活力的原因主要是由助表面活性剂醇造成的.     

Ceriporiopsis subvermispora used in delignification of sugarcane bagasse prior to soda/anthraquinone pulping

Sugarcane bagasse was pretreated with the white-rot fungus Ceriporiopsis subvermispora for 30 d of incubation. The solid-state fermentation of 800 g of bagasse was carried out in 20-L bioreactors with an inoculum charge of 250 mg of fungal mycelium/kg of bagasse. The oxidative enzymes manganese peroxidase (MnP), lignin peroxidase (LiP), and lac-case (Lac) and the hydrolytic enzyme xylanase (Xyl) were measured by standard methods and related to the fungus’s potential for delignification. Among the lignocellulolytic assayed enzymes, Xyl was detected in larger quantity (4478 IU/kg), followed by MnP (236 IU/kg). LiP and Lac were not detected. The results of chemical analysis and mass component loss showed that C. subvermispora was selective to lignin degradation. Pretreated sugarcane bagasse and control pulps were obtained by soda/anthraquinone (AQ) pulping. Pulp yields, kappa number, and viscosity of all pulps were determined by chemical analysis of the samples. Yields of soda/AQ ranged from 46 to 54%, kappa numbers were 15–25, and the viscosity ranged from 3.6 to 7 cP for pulps obtained from pretreated sugarcane bagasse.     

Induction of Cryptococcus laurentii α-galactosidase

The surface activity of Cryptococcus laurentii ??-galactosidase can be significantly (up to 80 times) influenced by a carbon source present in a cultivation medium. Induction of this enzyme is stimulated by the presence of saccharides containing bound galactose. The highest activity observed when the cells grew in a lactose medium was probably a consequence of the absence of cleavage products serving as repressors (glucose). This idea is supported by the poor growth of cells in the medium with lactose as the carbon source. The induction of surface ??-galactosidase was accompanied by increased activities in cytosole. The membrane fraction also contained this enzyme, but the influence of the carbon source was not proportional. The induction of ??-galactosidase may play an important role in galactose metabolism of the genus Cryptococcus with a direct influence on the virulence of these capsular yeasts.     

Nano-assembly of manganese peroxidase and lignin peroxidase from P. chrysosporium for biocatalysis in aqueous and non-aqueous media

Development, characterization, and activity studies of nano-assemblies of lignin peroxidase (LiP), and manganese peroxidase (MnP) from Phanerochaete chrysosporium on flat surfaces as well as colloidal particles have been investigated. These assemblies of LiP and MnP were fabricated with polyelectrolytes-poly(ethylenimine) (PEI), poly(dimethyldiallylammonium chloride) (PDDA), and poly(allylamine) (PAH)-using a layer-by-layer self-assembly technique (LbL). Characterization of these assemblies on flat surfaces was monitored using quartz crystal microbalance (QCM), while assemblies on microparticles such as melamine formaldehyde (MF) were carried out with zeta potential analyzer (ZPA). A unique dynamic adsorption-desorption of the enzyme layers is observed during the assembly. All the nano-assemblies of LiP and MnP can effectively oxidize veratryl alcohol (VA) to its aldehyde for an extended period of time. The effect of different polyions and the number of polyion layers on the activities of LiP and MnP nano-assembly was also examined. It is observed that drying of enzyme layer during the assembly and the use of non-aqueous media, such as acetone can significantly reduce the activity of the enzymes. Enzyme activity reaches a minimum when the concentration of acetone is increased to 30%; however, the activity can be restored to its original value by increasing the concentration of aqueous media. Preliminary studies using assemblies of LiP and MnP on MF microparticles further demonstrate the feasibility of developing potential systems for degradation of environmental pollutants.     

Catalytic performance of lignin peroxidase in a novel reverse micelle

To enhance the catalytic activity of lignin peroxidase (LiP) in a reverse micelle, a synthesized two-tail nonionic surfactant N-gluconyl glutamic acid didecyl ester (GGDE) was used to formulate a novel reverse micelle. Based on the LiP catalyzed oxidation of veratryl alcohol (VA) in this novel GGDE/TritonX-100-cyclohexane-H(2)O reverse micelle, the effects of the size of the reverse micelle, the buffer pH, and the concentration of H(2)O(2) on the catalytic activity of LiP were investigated. Under the optimized conditions, the catalytic efficiency of LiP in the GGDE/TritonX-100 reverse micelle was 40 times higher than that in the AOT reverse micelle. The full expression of catalytic activity of LiP in this medium was mainly due to the lack of electrostatic interaction between LiP and the head group of GGDE and TritonX-100 and to the size fit between LiP and the inner water cavity of the reverse micelle.     

Application of an enzyme thermistor for the determination of glucose in complex fermentation media

An enzyme thermistor was used for on-line glucose determination during cultivation of Cephalosporium acremonium for a period of 160 h. The complex medium consisted of 100 g 1^?1 peanut meal. Automatic control and data registration were achieved by interfacing a process computer with the thermistor unit. Problem caused by long-term application are discussed. On-line and off-line data obtained with the enzyme thermistor are compared with the results obtained with a commercial glucose analyzer. The results of these experiments show that an enzyme thermistor can be used to determine glucose concentration in complex fermentation media under real cultivation conditions for about 60 h.     

Cellulase production and regulation byAgaricus bisporus

Cellulose is degraded during the growth of the cultivated mushroomA. bisporus on composted straw. At the time of sporophore enlargement, a marked increase in extracellular endocellulase activity occurs. A high level of enzyme activity is maintained during subsequent cropping cycles. Some of the factors affecting growth and production of extracellular endocellulase activity byA. bisporus cultured in simple defined liquid media have been examined. Endocellulase production by the fungus closely paralleled mycelial growth in cultures containing microcrystalline cellulose. The enzyme was induced by various celluloses and cellobiose. In the presence of a cellulose inducer, glucose and cellobiose repressed enzyme production. Endocellulase activity in culture filtrates was inversely related to cellulose concentration in the culture. Although the activity of free enzyme was low, in high concentrations of cellulose more cellulose was degraded. Evidence was obtained for the existence of two forms of endocellulase activity. One form adsorbed strongly to cellulose and was predominant in cultures low in cellulose. In cultures with a high cellulose content, a nonadsorbable form of the enzyme was more abundant. It is suggested that the pattern of cellulase activities produced whenA. bisporus is grown on different concentrations of cellulose is partly accounted for by its adsorption to the cellulose.     

Microbial synthesis of chitinase in solid cultures and its potential as a biocontrol agent against phytopathogenic fungus Colletotrichum gloeosporioides

Antifungal activity of chitinase can be effectively utilized in biologic pest control strategies. Because solid-state cultivation has been termed a cost-effective means for fungal growth and metabolite production, chitinase production by Trichoderma harzianum was studied using wheat bran-based solid medium containing 1% colloidal chitin. Chitinase synthesis was found to be growth associated because maximum enzyme (5.4 U/g of dry substrate) and biomass production occurred at 72h. Substrate moisture had a critical impact on chitinase production; five grams of medium having an initial moisture content of 68.4% when incubated for 72 h increased the enzyme yield to 9.3 U/g of dry substrate. Optimization of colloidal chitin concentration showed that improvements in chitinase yield and maximum activity were attained with a 2% (w/w) concentration. Supplementation of additional nitrogen sources also influenced enzyme production, and the best yield was obtained with yeast extract. The effect of crude chitinase on hyphal morphology of the phytopathogenic fungus Collelotrichum gloeosporioides was swelling as well as lysis of hyphal wall, depending on the age of the mycelium. Studies of pH and thermal stability showed that crude culture filtrate was active over pH 4.0–6.0 and retained about 48.2% activity after 40 min of incubation at 40°C.     

Activity Regulation of Lignin Peroxidase from Phanerochaete chrysosporium in Nonionic Reversed Micellar Medium

The activity of lignin peroxidase (LIP) in reversed micelles of polyoxy ethylene laurylether (Brij30) changed with the molar ratio of water to the surfactant and the denaturant concentration of guanidinium chloride. At low water contents the activity of LiP could be enhanced by the denaturant at moderate concentration. This phenomenon, together with the spectral characteristics of the intrinsic fluorescence of LiP, suggested that the conformation of the active center of LIP was flexible.     

Investigations on Hydrolytic Activities from Stachybotrys microspora and Their Use as an Alternative in Yeast DNA Extraction

Stachybotrys microspora is a filamentous fungus characterized by the secretion of multiple hydrolytic activities (cellulolytic and non-cellulolytic enzymes). The production of these biocatalysts was studied under submerged culture using glucose, cellulose, and wheat bran as carbon sources. Endoglucanases, pectinases, xylanases, β-glucanases, chitinases, and proteases were induced on cellulose-based medium and repressed on glucose in both strains with higher amounts produced by the mutant. β-glucosidases were roughly equally produced by both strains under glucose and cellulose conditions. The yield of chitinases, β-glucanases, and proteases produced by Stachybotrys strains was as much higher than the commercialized lysing enzyme called “zymolyase,” currently used in yeast DNA extraction. In this context, we showed that S. microspora hydrolases can be successfully applied in the extraction of yeast DNA.     

Effect of Phosphate on Glucosamine Production by Ethanolic Fungus Mucor indicus

In this study, the effect of phosphorous compound concentration on the production of glucosamine by Mucor indicus was investigated. Changes in the yield of ethanol, the major metabolite of the fungus, were also followed besides. The alkali insoluble material of the biomass of the fungus mainly contained phosphates and polymers of glucosamine and N-acetyl glucosamine, i.e., chitin and chitosan. Yields of glucosamine (78–113 g/kg dry fungal biomass) and ethanol (200–370 g/kg glucose) were significantly affected by the phosphorous concentration. The results showed that lower concentrations of phosphorous favored the production of glucosamine while higher ethanol as well as biomass yields was obtained at higher concentrations. The best concentration was 0.5 g/l where glucosamine yield was 0.37 g/l (11 % of the biomass). At this phosphate concentration, ethanol and biomass yields were 360 and 76 g/kg glucose, respectively. On average, proteins comprised 51.5 % of the biomass. Glycerol was the second important metabolite during the fermentation by the fungus which appeared at lower yields (20–34 g/kg glucose).     

Lipase production byPenicillium restrictum in a bench-scale fermenter

A preliminary screening work selectedPenicillium restrictum as a promising micro-organism for lipase production. The physiological response of the fungus towards cell growth and enzyme production upon variable carbon and nitrogen nutrition, specific air flow rate (Qa) and agitation (N) was evaluated in a 5-L bench-scale fermenter. In optimized conditions for lipase production meat peptone at 2% (w/v) and olive oil at 1% (w/v) were used in a growth medium with a C/N ratio of 9.9. Higher C/N ratios favored cell growth in detriment of enzyme production. Low extracellular lipase activities were observed using glucose as carbon source suggesting glucose regulation. Final lipase accumulation of 13,000 U/L was obtained, using optimized specific air flow rate (Qa) of 0.5 wm and an impeller speed (N) of 200 rpm. Agitation showed to be an important parameter to ensure nutrient availability in a growth medium having olive oil as carbon source.     

Oxidation of crocein orange G by lignin peroxidase isoenzymes

The ligninolytic enzyme system ofPhanerochaete chrysosporiun is able to decolorize several recalcitrant dyes. Three lignin peroxidase isoenzymes, LiP 3.85, LiP 4.15, and LiP 4.65, were purified by preparative isoelectric focusing from the carbon-limited culture medium ofP. chrysosporium. Based on amino terminal sequences, the purified isoenzymes correspond to the isoenzymes H8, H6, and H2, respectively, from theN-limited culture. The purified isoenzymes were used for decolorization of an azo dye, Crocein Orange G (COG). According to the kinetic data obtained, the oxidation of COG by lignin peroxidase appeared to follow Michaelis-Menten kinetics. Kinetic parameters for each isoenzyme were determined. The inactivating effect of ascending H₂O₂ concentrations on COG oxidation is shown to be exponential within the used concentration range. The best degree of decolorization of 100 μM COG was obtained when the H₂O₂ concentration was 150 μM. This was also the lowest H₂O₂ concentration for maximal decolorization of 100 μM COG, regardless of the amount of lignin peroxidase used in the reaction.