LiP Activities Research Articles

Screening of White-Rot Fungi Isolates for Decolorization of Pulp and Paper Mill Effluent and Assessment of Biodegradation and Biosorption Processes.

Ten white-rot fungal isolates were evaluated for the decolorization potential of pulp and paper mill effluent. Trametes elegans PP17-06, Pseudolagarobasidium sp. PP17-33, and Microporus sp.2 PP17-20 showed the highest decolorization efficiencies between 42 and 54% in 5 d. To reveal the mechanisms involved in decolorization and assess the long-term performance, PP17-06, which showed the highest decolorization efficiency, was further investigated. It could reduce the ADMI color scale by 63.6% in 10 d. However, extending the treatment period for more than 10 d did not significantly enhance the decolorization efficiencies. The maximum MnP activity of 3.27 U L-1 was observed on the 6 d during the biodegradation. In comparison, laccase activities were low with the maximum activity of 0.38 U L-1 (24 d). No significant LiP activities were monitored during the experiment. Dead fungal biomass showed an optimum decolorization efficiency of 44.18% in 8 d employing the biosorption mechanism. No significant changes in the decolorization efficiency were observed after that, suggesting the equilibrium status was reached. These results revealed that PP17-06 has the potential to decolorize pulp and paper mill effluent by employing both biodegradation and biosorption processes.

Sediment Resuspension and Associated Extracellular Enzyme Activities Measured ex situ: A Mechanism for Benthic-Pelagic Coupling in the Deep Gulf of Mexico

Sediment resuspension caused by near-bed currents mediates exchange processes between the seafloor and the overlying water column, known as benthic-pelagic coupling. To investigate the effects of sediment resuspension on microbial enzyme activities in bottom waters (<500 m), we conducted onboard erosion experiments using sediment cores taken with a multi-corer from six deep-sea sites in the northern Gulf of Mexico. We then incubated the core-top water with resuspended sediments in roller tanks to simulate bottom water conditions following sediment resuspension. Bacterial cell abundance, particulate organic matter content, and potential rates of three hydrolytic enzymes (leucine aminopeptidases – PEP; β-glucosidases – GLU, lipases – LIP) were monitored during the experimentally-generated erosion events and subsequently in the roller tanks to examine whether resuspension of deep-sea sediments enhances activities of extracellular enzymes in overlying waters. Surficial sediments were resuspended at critical shear stress velocities between 1.4 and 1.7 cm s–1, which parallel bottom water currents of 28 and 34 cm s–1. Only one of our nine cores resisted experimentally generated bottom shear stresses and remained undisturbed, possibly as a result of oil residues from natural hydrocarbon seeps at the investigated site. The most notable enzymatic responses to sediment resuspension were found for LIP activities that increased in overlying waters of all eight of our resuspended cores and remained at high levels during the roller tank incubations. PEP and GLU showed orders of magnitude lower rates and more variable responses to experimentally resuspended sediments compared with LIP. We also found a disconnect between enzyme activities and bacterial cell numbers, indicating a major role of extracellular enzymes physically disconnected from microbial cells in our experiments. Our results demonstrate that sediment resuspension may promote organic matter breakdown in bottom waters by supplying extracellular enzymes without requiring a bacterial growth response. The marked increase in LIP activity suggests that resuspended enzymes may affect the degradation of petroleum hydrocarbons, including those from the natural seeps that are abundant in the investigation area.

Lignocellulolytic enzyme activity pattern of three white oyster mushroom (Pleurotus ostreatus (Jacq.) P. Kumm.) strains during mycelial growth and fruiting body development

Pleurotus ostreatus is one of the edible mushrooms that can utilize lignocellulose as substrate because of their ability to secrete the lignocellulolytic enzyme. The purpose of this research is to investigate and compare the lignocellulolytic enzymes production of P. ostreatus InaCC F209, F216 and LIPI on solid-state fermentation using sawdust during 70 days of mycelial growth (vegetative phase) and fruiting body development (reproductive phase). Supernatant of the extracted enzyme solutions were employed to investigate the reducing sugar, soluble protein, and enzyme activities. The results revealed that reducing sugar concentration of the three P. ostreatus strains subjected increased during growth and reached the maximum concentration on the reproductive phase, while the total protein content fluctuated during the growth but reached the maximum concentration on the reproductive phase. Laccase, LiP, and MnP activities of three P. ostreatus strains were higher on the vegetative phase, while the endoxylanase and endoglucanase activities were higher on the reproductive phase. β-glucosidase activity showed different variations between three P. ostreatus strains. Pleurotus ostreatus InaCC F209 produced the highest and most stable laccase, β-glucosidase, endoglucanase, and endoxylanase than two others.

Toxicity of perfluorooctane sulfonate on Phanerochaete chrysosporium: Growth, pollutant degradation and transcriptomics

As a persistent organic pollutant listed in the Stockholm Convention, perfluorooctane sulfonate (PFOS) is extremely refractory to degradation under ambient conditions. Its potential ecotoxicity has aroused great concerns and research interests. However, little is known about the toxicity of PFOS on fungus. In this study, the white rot fungus Phanerochaete chrysosporium (P. chrysosporium) was adopted to assess the toxicity of PFOS in liquid culture. The addition of 100 mg/L PFOS potassium salt significantly decreased the fungal biomass by up to 76.4% comparing with un-amended control during the incubation period. The hyphostroma of P. chrysosporium was wizened and its cell membrane was thickened, while its vesicle structure was increased, based on the observation with scanning electron microscope (SEM) and transmission electron microscope (TEM). Nevertheless, the PFOS dosage of below 100 mg/L did not show a considerable damage to the growth of P. chrysosporium. The degradation of malachite green (MG) and 2,4-dichlorophenol (2,4-DCP) by P. chrysosporium was negatively affected by PFOS. At the initial dosage of 100 mg/L PFOS, the decolorization efficiency of MG and the degradation efficiency of 2,4-DCP decreased by 37% and 20%, respectively. This might be attributed to the inhibition of PFOS on MnP and LiP activities. The activities of MnP and LiP decreased by 20.6% and 43.4%, respectively. At a high dosage PFOS (100 mg/L), P. chrysosporium could show a high adsorption of MG but lose its pollutant degradation ability. Transcriptome analysis indicated that PFOS contamination could lead to the change of gene expression in the studied white rot fungus, and the genes regulating membrane structure, cell redox process, and cell transport, synthesis and metabolism were impacted. Membrane damage and oxidative damage were the two main mechanisms of PFOS’ toxicity to P. chrysosporium.

Isolation of Streptomyces sp. Strains Capable of Degrading Lignin Under Alkaline Conditions and Its Degradation Properties

A bacterial strain (designated as Y-8), capable of efficiently degrading lignin under alkaline conditions, was isolated from saline-alkali soil and identified as Streptomyces sp. based on the morphological and physiological analyses as well as the gene sequences comparison of the 16 S rDNA. The alkali tolerance and lignin degradation capability of the isolated strain were determined. The results indicated that Streptomyces sp. Y-8 achieved the optimum lignin degradation at a temperature of 35 degrees C and a pH value of 9.5 with sucrose as the auxiliary carbon source and ammonium nitrate as the nitrogen source, reaching 32.6% in seven days. In addition, the activity of the three enzymes that were produced from the lignin degradation by Streptomyces sp. Y-8 under alkaline conditions (pH = 9.5), laccase (Lac), lignin peroxidase (Lip), and manganese peroxidase (MnP) was studied. The results indicated that the Lac and Lip activities reached their respective maximums on the fifth and fourth day of lignin degradation, respectively, being 4583.5 U/L, and 1163.2 U/L, respectively, and almost no MnP was detected throughout the process. This study is of great significance to the biological pretreatment of lignocellulose or the treatment of black liquid produced from papermaking under alkaline conditions.

Cotton Stalk Pretreatment Using Daedalea flavida, Phlebia radiata, and Flavodon flavus: 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 25days 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 20days. Xylanase was predominant cellulolytic enzyme produced by DF-2, resulting hemicellulose as main carbon and energy source with 83% of cellulose recovery after 40days of pretreatment. The glucose yield improved more than two fold from 20-day DF-2 pretreated cotton stalks after enzymatic saccharification.

Lignocellulose-degrading enzyme production by Pleurotus sapidus WC 529 and its application in lignin degradation / Lignoselüloz-çözücü enzim üretiminde Pleurotus sapidus WC 529 ve lignin parçalanmasındaki uygulamaları

Abstract Objective: Cost-effective production of industrially important enzymes is a key for their successful utilization on large scale. Present study was conducted to appraise Pleurotus sapidus WC 529 potential to produce oxidative (lignin peroxidase, manganese peroxidase, laccase) and hydrolytic (endoglucanase, exoglucanase and β-glucosidase) enzymes, grown on wheat straw, corn cobs, corn stover, rice straw, banana stalk and sugarcane bagasse in solid state fermentation (SSF) process. The crude extract thus produced was used for the delignification of various agro-industrial residues. Methods: Different agricultural wastes were assessed for lignocellulolytic enzymes production. The process parameters were optimized through response surface methodology (RSM) with central composite design (CCD) for maximum enzyme production. Results: P. sapidus secreted lower levels of hydrolytic enzymes but expressed high laccase, MnP and LiP activities in SSF (228.25, 153.45 and 59.20 UmL-1 respectively) of banana stalk. The optimal conditions for yielding highest enzyme activities were: initial pH, 4; temperature, 35°C; moisture level, 60%; inoculum size, 4 mL, and incubation time, 120 h. The enzyme extract removed 56.54, 51.08, 65.81 and 57.4% lignin from rice straw, sugarcane bagasse, corn cobs and wheat straw, respectively, after 48 h at 35°C. Conclusion: High ligninolytic activities were obtained in SSF of banana stalk by P. sapidus. The enzyme production was considerably improved by optimization through RSM. The results suggest that lignocellulolytic enzymes could be produced using cost-effective carbon sources and implicated to digest lignocellulosic biomass.

Investigation of physico-chemical properties and microbial community during poultry manure co-composting process

Co-composting of poultry manure and rubber wood sawdust was performed with the ratio of 2:1 (V/V) for a period of 60days. An investigation was carried out to study the extracellular enzymatic activities and structural degradation utilizing Fourier transform infrared spectroscopy (FT-IR), thermogravimetry and differential thermal analysis (TG/DTA) and scanning electron microscopy (SEM). The microbial succession was also determined by using denaturing gel gradient electrophoresis (DGGE). The compost was able to reach its highest temperature of 71°C at day 3 and stabilized between 30 and 40°C for 8weeks. CMCase, FPase and β-glucosidase acted synergistically in order to degrade the cellulosic substrate. The xylanase activities increased gradually during the composting and reached the peak value of 11.637U/g on day 35, followed by a sharp decline. Both LiP and MnP activities reached their peak values on day 35 with 0.431 and 0.132U/g respectively. The FT-IR spectra revealed an increase in aromaticity and a decrease in aliphatic compounds such as carbohydrates as decomposition proceeded. TGA/DTG data exhibited significant changes in weight loss in compost samples, indicating degradation of organic matter. SEM micrographs showed higher amounts of parenchyma exposed on the surface of rubber wood sawdust at day 60, showing significant degradation. DGGE and 16S rDNA analyses showed that Burkholderia sp., Pandoraea sp., and Pseudomonas sp. were present throughout the composting process. Ornithinibacillus sp. and Castellaniella ginsengisoli were only found in the initial stage of the composting, while different strains of Burkholderia sp. also occurred in the later stage of composting.

Isolating, evaluating and optimizing lignocellulosic decomposition of various microbial strains

This research was conducted in order to find out active strains those can well decompose and remove lignin from agricultural waste sources for the production of biofuels by biological pathways. Fiffty fungal strains were isolated and assessed degree of lignin and cellulose degradation based on speed and diameter of round-resolution on lignin and CMC medium. The experiment was expected to select highly active strains in biomass degradation ability. The selected strains were determined enzymatic activities including Lignin peroxidase, Manganese peroxidase and Cellulase. We also tested factors those could affect the biosynthesis of lignin and cellulose enzymes, it was indicated that the 4 strains: strains 5, 10, 14 and P201 were superior as compared with other strains. Based on enzyme assay, the strain 10 shown up to 163.391 UI/L 0.838 UI/L and 1098.914 UI/L for LiP, MnP and cellulase activities, respectively, this strain was considered to be the most active on both ligninase and cellulase systems. The obtained results also showed that avicel medium was suitable for the biosynthesis of cellulase enzyme; While, PGB medium was suitable for biosynthesis enzyme ligninase system. LiP activity was highest on the fifth day in PGB medium; with a value of 223.587 UI/L. MnP activity reached maximal value ​​on the third day in PGB medium with a value of 0.935 UI/L. For cellulase enzyme systems, enzymatic activity on avicel medium was higher on PGB medium and achieved the highest value on the third day with a value of 2340.148 IU/L.

A Functional Hierarchy within the Parietofrontal Network in Stimulus Selection and Attention Control

Although we are confronted with an ever-changing environment, we do not have the capacity to analyze all incoming sensory information. Perception is selective and is guided both by salient events occurring in our visual field and by cognitive premises about what needs our attention. Although the lateral intraparietal area (LIP) and frontal eye field (FEF) are known to represent the position of visual attention, their respective contributions to its control are still unclear. Here, we report LIP and FEF neuronal activities recorded while monkeys performed a voluntary attention-orientation target-detection task. We show that both encode behaviorally significant events, but that the FEF plays a specific role in mapping abstract cue instructions onto a spatial priority map to voluntarily guide attention. On the basis of a latency analysis, we show that the coding of stimulus identity and position precedes the emergence of an explicit attentional signal within the FEF. We also describe dynamic temporal hierarchies between LIP and FEF: stimuli carrying the highest intrinsic saliency are signaled by LIP before FEF, whereas stimuli carrying the highest extrinsic saliency are signaled in FEF before LIP. This suggests that whereas the parietofrontal attentional network most probably processes visual information in a recurrent way, exogenous processing predominates in the parietal cortex and the endogenous control of attention takes place in the FEF.

A computational model of posterior parietal circuits during decision making and sequential planning

In the posterior parietal cortex (PPC), three anatomically separated but reciprocally interconnected subareas, the lateral intraparietal area (LIP), parietal reach region (PRR) and dorsal area 5 (area 5d), are involved in sensorimotor transformation during planning of eye/arm movements. We have previously designed the saccade/reach effector choice and sequential reach paradigms to dissociate cognitive and executive planning activity in PPC. During saccade/reach choice, LIP and PRR encodes potential saccade/reach plans in parallel before effector decision is formed, and the selected saccade/reach plans thereafter [1], whereas area 5d only reflects the decision outcome [2]. During sequential reach, PRR encodes both immediate and subsequent goals [3], whereas area 5d only represents the immediate upcoming reach [4]. Based on the experimental results above, we propose a network model to conceive the functional connectivity across these areas. The model is composed of an upstream layer representing the abstract motor intentions and a down-stream layer representing concrete motor commands. The up-stream layer consists of LIP and PRR neurons preferring different directions for saccade and reach, respectively, and two populations compete against each other. The down-stream layer is composed of area 5d neurons preferring arm movements to different directions. In each neuronal pool, each leaky integrate-andfire neuron excites others representing nearby targets but inhibits the remaining. The up-stream layer also feed-forwards to the down-stream layer to excite the neurons preferring the same effector and nearby target but to inhibit others. Furthermore, each LIP and PRR neuron receives self-excitation whose magnitudes are modulated by the rule-based behavioral context, reflecting the topdown feedback. Our simulation results show that, during the effector choice and instructed tasks, the effector information is ambiguous at first so that both LIP and PRR show strong responses and counterbalance the total input to area 5d. Once effector information is determined by either choice or instruction, LIP and PRR activities differentiate to trigger or suppress area 5d activity. During the classical memory saccade/reach tasks, effector information is given at the cue onset so that LIP and PRR activities began to differentiate and area 5d fires immediately. During the sequential reaching task, after two targets are simultaneously presented, the activity of the PRR encoding the 1st goal increases faster while the activity of the PRR encoding the 2nd goal increases slower but lasts longer due to the different recurrent connections modulated by the behavioral context. Consequentially, only the activity of the area 5d neuron encoding the 1st goal is elevated before the GO signal. Once the first reach is completed, the area 5d neuron preferring the 2nd goal begins to fire because top-down context information (efference copy in this case) reduces the strength of recurrent connection for the PRR neuron coding the 1st goal. Preliminary results indicate that our model captures all characteristics of neural activity we have observed so far. Our ongoing modeling work will help reveal the network mechanisms underlying the operation of the parietal sensorimotor circuits.

Biological characteristics of five wood-rotting fungi and wood-decaying ability to Betula platyphylla

In this paper, the growth rate of five wood-rotting fungi, i.e., Coriolus versicolor, Irpex lacteus, Fomes fomentarius, Piptoporus betulinus and Pholiota adiposa, in solid medium and their biomass in liquid culture medium were compared by measuring mycelium length and dry mass. The activity of three main ligninolytic enzymes in those fungi, namely LiP, MnP and Lac, were also tested by colorimetry. At the same time, these fungi were used to decay the wood samples from 300 natural trees of white birch, to study their wood-decaying ability by measuring wood mass loss. The result showed that the growth rate, biomass, ligninolytic enzyme activity, and wood-decaying ability of the fungi were incompletely correlated. The growth rates of C. versicolor and I. lacteus were faster than those of P. betulinus and F. fomentarius; P. adiposa was the slowest in growth. The biomass of P. betulinus was the highest; C. versicolor, I. lacteus and F. fomentarius were in the middle, and P. adiposa was the lowest. There existed LiP, MnP and Lac activities in all fungi except P. betulinus, and the enzyme activities induced by wood powder were all higher than those of the control. The Lac of I. lacteus and the LiP of F. fomentarius and P. adiposa were only expressed in wood powder medium; the longer the fungi were cultured, the higher activity the enzyme had. The decomposition ability of C. versicolor to wood samples was the highest, followed by F. fomentarius and P. betulinus; I. lacteus and P. adiposa were the lowest.

Biological treatment of the effluent from a bleached kraft pulp mill using basidiomycete and zygomycete fungi

Three white-rot fungi ( Pleurotus sajor caju, Trametes versicolor and Phanerochaete chrysosporium) and one soft-rot fungi ( Rhizopus oryzae) species confirmed their potential for future applications in the biological treatment of effluents derived from the secondary treatment of a bleached kraft pulp mill processing Eucalyptus globulus. Among the four species P. sajor caju and R. oryzae were the most effective in the biodegradation of organic compounds present in the effluent, being responsible for the reduction of relative absorbance (25–46% at 250 nm and 72–74% at 465 nm) and of chemical oxygen demand levels (74 to 81%) after 10 days of incubation. Laccase (Lac), lignin (Lip) and manganese peroxidases (MnP) expression varied among fungal species, where Lac and LiP activities were correlated with the degradation of organic compounds in the effluent treated with P. sajor caju. The first two axes of a principal component analysis explained 88.9% of the total variation among sub-samples treated with the four fungus species, after different incubation periods. All the variables measured contributed positively to the first component except for the MnP enzyme activity which was the only variable contributing negatively to the first component. Absorbances at 465 nm, LiP and Lac enzyme activities were the variables with more weight on the second component. P. sajor caju revealed to be the only species able to perform the biological treatment without promoting an increment in the toxicity of the effluent to the Vibrio fischeri, as it was assessed by the Microtox® assay. The opposite was recorded for the treatments with the other three species of fungus. EC 50–5 min values ranging between 28 and 57% (effluent concentrations) were recorded even after 10 to 13 days of treatment with P. chrysosporium, R. oryzae or with T. versicolor.

Biodegradation of Methyl red by Galactomyces geotrichum MTCC 1360

Galactomyces geotrichum MTCC 1360 can decolorize triphenylmethane, azo and reactive high exhaust textile dyes. At shaking condition this strain showed 100% decolorization of a toxic azo dye Methyl red (100 m gl −1) within 1 h in deionized water at 30 °C. The degradation of Methyl red was possible through a broad pH (3–12) and temperature (5–50 °C) range. Glucose and mycelium concentration had increased the decolorization rate, but the addition of 1 gl −1 molasses in deionized water made decolorization possible in only 10 min. Induction in the NADH–dichloro phenol indophenol (NADH–DCIP) reductase, Malachite green reductase, laccase and lignin peroxidase (Lip) activities were observed in the cells obtained after complete decolorization, showing that there is direct involvement in the degradation of Methyl red. The absence of N- N′-dimethyl-p-phenylenediamine (DMPD) in 5 °C, 2-aminobenzoic acid (ABA) in 50 °C and both the compounds in 30 °C sample have shown the differences in the metabolic fate of Methyl red at different temperatures. The untreated dye at 300 mg l −1 concentration showed 88% germination inhibition in Sorghum bicolor, whereas it was 72% in Triticum aestivum. There was no germination inhibition for both the plants by Methyl red metabolites at 300 mg l −1 concentration. The scientific relevance of the paper The azo dye Methyl red (100 mg l −1) was decolorized by G. geotrichum MTCC 1360 within 1 h at shaking condition in deionized water. This organism could decolorize Methyl red at wide pH and temperature ranges. Decolorization time was reduced to 10 min by the addition of molasses to deionized water. There was induction in laccase and Lip, NADH–DCIP reductase and Malachite green reductase activities. The metabolic fate of Methyl red changes with temperature which can be evidenced by the formation of 2-ABA at 5 °C, N- N′-DMPD at 50 °C and both the compounds were absent at 30 °C. Phytotoxicity showed that metabolites of dye had induced shoot and root length of both the tested plants.

Enzymes produced by Ganoderma australe growing on wood and in submerged cultures

Enzymes produced by Ganoderma australe in solid-state fermentation and submerged cultures were evaluated. Strain A464 produced laccase activity in liquid medium and in solid-state cultures containing Drimys winteri or Eucalyptus globulus wood chips, while MnP and LiP activities were not detected. On the other hand, strain A272 cultured for 75 days on E. globulus presented MnP activity of 719 IU/kg of wood. The suitability of D. winteri wood as a substrate enabling MnP production was checked with a well-documented MnP-producing basidiomycete, Ceriporiopsis subvermispora, which produced MnP activity of 327 IU/kg of wood in 9-day-old cultures. Data from two different G. australe strains (A272 and A464) indicated that MnP secretion depended on strain origin as well as on culture conditions.

Purification and Characterization of Lipase in Buckwheat Seed

To obtain basic information about enzymatic deterioration of buckwheat flour, triacylglycerol lipase (LIP; EC 3.1.1.3) was purified from buckwheat seed. The LIP consisted of two isozymes, LIP I and LIP II, and they were purified with purification folds of 60 and 143 with final specific activities of 0.108 and 0.727 mumol of fatty acid released per minute per milligram of protein at 30 degrees C using triolein as a substrate. Molecular weights were estimated to be 150 (LIP I) and 28.4 kDa (LIP I) by gel filtration and 171 (LIP I) and 26.5 kDa (LIP II) by SDS-PAGE. Optimal pHs of LIP activities were 3.0 (LIP I) and 6.0 (Lip II) using triolein as a substrate. Both LIP I and II reacted in the acidic pH range. Optimal temperatures were 30 (LIP I) and 40 degrees C (LIP II), and both LIP I and II were stable below 30 degrees C when p-nitrophenyl-laurate was used as a substrate. However, they were inactivated above 60 degrees C. On the other hand, when triolein was used as a substrate, optimal temperatures were 30 degrees C for both LIP I and II, and they retained 40% of their activity after a 4 h incubation of enzymes at 70 degrees C. LIP I and II had higher activity against triolein than monoolein or tri/monopalmitin. Most of the LIP activity was distributed in the embryo.

Development of lip treatment on the basis of desquamation mechanism

Lip chapping is a serious cosmetics problem, though remedies other than moisturization have not been proposed. We investigated changes in the surface configurations of lip corneocytes and activities of desquamation‐regulating proteinases associated with lip chapping. Using scanning electron microscopy, villus‐like projections were observed on the inner surfaces of most corneocytes from normal lips, whereas those with flatter surface were predominantly found in chapped lips. Furthermore, cell surface area increased with the severity of lip chapping. Cathepsin D‐like and chymo‐trypsin‐like proteinase, which are also present in skin as desquamation‐regulating proteinases, were detected in lip corneocytes, though only cathepsin D activity was found to decrease in severely chapped lips. Hydration was also lower in areas of lip chapping. Sequential topical application of apricot extract essence increased cathepsin D activity and improved chapping severity. Our results suggest that lip chapping can be characterized as similar to senile xerosis rather than dry skin such as winter xerosis, as it shows a delayed transition of corneocytes through the stratum corneum, and the reduced cathepsin D activity may be one of the mechanisms that is further decreased by low hydration. We propose that an enhancement of both cathepsin D activity and lip moisture may be effective to improve lip chapping.

Lignin-Degrading Enzymes from Mycelial Cultures of Basidiomycete Fungi Isolated in Tanzania

This research involved field surveys in different geographical locations in Tanzania for collection of fungi species, identification of the isolates, and screening for lignin-degrading enzyme production. Out of 18 saprophytic fungi (both wood and non-wood inhabiting) isolates, 17 were positive in the rhemazol brilliant blue-R (RBBR) decolorization test; 15 of the isolates oxidized guaiacol while 7 and 12 oxidized α-naphthol and pyrogallol, respectively. The cultures with 1% glucose concentration showed the fastest growth of mycelia and highest MnP, LiP, and Lac activities. MnP was found to be dominant among the tested isolates and Laetiporus sulphurae had the highest LiP activity of 65.2 U/ml. Most of the fungi isolates produced more than two extracellular enzymes, suggesting that these isolates possess the ability to degrade lignin or related polyphenolic compounds, and thus they can be used in upgrading low quality animal feed. The selected fungi isolates reduced cellulose and hemicellulose contents in rice straw by an average of 10% and 35%, respectively, delignification ratio of 23% and increased its relative crude protein content by more than 50%.

Ligninolytic Enzymes of the White Rot BasidiomyceteTrametes trogii

The white rot fungus Trametes trogii strain BAFC 463 produced laccase, manganese peroxidase, lignin peroxidase and cellobiose dehydrogenase, as well as two hydrogen peroxide-producing activities: glucose oxidizing activity and glyoxal oxidase. In high-N (40 mM N) cultures, the titres of laccase, MnP and GLOX were 27 (6.55 U/ml), 45 (403.00 mU/ml)and 8 (32,14 mU/ml) fold higher, respectively, than those measured in an N-limited medium. This is consistent with the fact that the ligninolytic system of T. trogii is expressed constitutively. Lower activities of all the enzymes tested were recorded upon decreasing the initial pH of the medium from 6.5 to 4.5. Adding veratryl alcohol improved GLOX production, while laccase activity was stimulated by tryptophan. Supplying Tween 80 strongly reduced the activity of both MnP and GLOX, but increased laccase production. The titre of MnP was affected by the concentration of Mn in the culture medium, the highest levels were obtained with 90 μM Mn (II). LiP activity, as CDH activity, were detected only in the mediumsupplemented with sawdust. In this medium, laccase production reached a maximum of 4.75 U/ml, MnP 747.60 mU/ml and GLOX 117.11 mU/ml. LiP, MnP and GLOX activities were co-induced, attaining their highest levels at the beginning of secondary metabolism, but while MnP, laccase, GLOX and CDH activities were also present in the primary growth phase, LiP activity appears to beidiophasic. The simultaneous presence of high ligninolytic and hydrogen peroxide producing activities in this fungus makes it an attractive microorganism for future biotechnological applications.

Lignin-degrading enzyme production by Bjerkandera adusta immobilized on polyurethane foam

Production of the lignin-degrading enzymes lignin peroxidase (Lip), manganese peroxidase (MnP), and laccase (Lac) by the white-rot fungus Bjerkandera adusta was investigated experimentally using polyurethane foam (PUF) as a carrier of immobilized fungal mycelia. An immobilized cell culture with a low-nitrogen medium yielded significantly greater LiP, MnP, and Lac activities in comparison with those obtained in a liquid culture. The maximum activities of the three enzymes were 450, 370, and 100 U/ml, respectively, under the following incubation condition: glucose concentration, 20 g/ l; temperature, 30°C; pH 4.5. The activities of MnP and Lac were significantly higher than those reported using other incubation methods. Lignin was degraded to the extent of 40% and its decolorization ratio was about 70% at an incubation time of 40 h using lignin-degrading enzymes from B. adusta. Six different isozymes of MnP were synthesized by B. adusta, two of which exhibited high MnP activity. Our preliminary finding that extracellular enzymes from B. adusta are capable of degrading and decoloring lignin makes these enzymes attractive for further research aimed at their large-scale application in lignin depolymerization, pulp biobleaching, and the degradation of toxic pollutants.