Lac Production Research Articles

Catalytic effect of metal nitrate salts during pyrolysis of impregnated biomass

Catalytic pyrolysis is a promising way to improve bio-oil product quality. In this study, metal salts were directly impregnated in biomass to generate in situ catalysts and investigate their impact on pyrolysis products. Seven metals – Ce, Mn, Fe, Co, Ni, Cu and Zn – were selected and impregnated in eucalyptus using nitrate salts. A fixed-bed reactor, pre-heated at 500°C and inerted with N2 flow, was used for pyrolysis. Both gas and bio-oil compositions were analysed, paying particular attention to the production of anhydrosugars. The anhydrosugar yields were found to be strongly influenced by the presence of metal salt catalysts. In particular, both Zn and Co salts yielded more anhydrosugars in comparison with catalyst-free sample. Moreover, LAC (1-hydroxy-(1R)-3,6-dioxabicyclo[3.2.1]octan-2-one) was produced in higher amounts than levoglucosan which is commonly produced without any catalyst. Metals were found to remain in all chars and tended to form metal-based nanoparticles (e.g. Cu0, Ni0, ZnO) able to act as in situ catalysts during the pyrolysis process. It seems that those metal nanoparticles are closely related to LAC production. In parallel to metal cations, nitrates were also suspected to play a significant role during pyrolysis. The suspected impact of anions on levoglucosenone production is discussed. Concerning gas yields, the impregnated nitrate salts were found to strongly affect CO2 production.

Upgraded production of (1R,5S)-1-hydroxy-3,6-dioxa-bicyclo[3.2.1]octan-2-one from cellulose catalytic pyrolysis and its detection in bio-oils by spectroscopic methods

Catalytic pyrolysis of cellulose was carried out focusing on the selective production of the anhydrosugar (1R,5S)-1-hydroxy-3,6-dioxa-bicyclo[3.2.1]octan-2-one (LAC), a promising chiral chemical for application in organic synthesis. The catalyst Sn-MCM-41, montmorillonite K10 or aluminum titanate nanopowder was used by a suitable pyrolysis reactor performing the processes at 500°C and 350°C. After a workup adapted to optimize the production of LAC and to facilitate the following purification, its amount in the produced bio-oil samples was established by 1H NMR spectroscopy using the standard-addition method. A further quantitative analysis was based on FT-IR technique performed using a CaF2 liquid cell and employing the calibration-curve method. Both the methods, which do not require any pre-treatment steps, provided comparable values (±1%) in terms of LAC abundance in bio-oil samples and validation of the FT-IR based method made it a rapid and efficient tool for quantitative LAC detection also without need of carbonyl band deconvolution. The data showed that (i) Sn-MCM-41 promoted the highest LAC production by pyrolysis at 500°C (7.6±0.1wt.% from cellulose), with a lower than 1% decrease in the presence of this catalyst after a regeneration cycle, and (ii) the cheap and eco-friendly montmorillonite K10 emerged as the best alternative, with a yield from cellulose of 4.8±0.1wt.% at 500°C and 4.6±0.1wt.% at 350°C.

First Record of Some Insect Pests on Commercial Lac Host Plant, Ziziphus mauritiana from India

Ziziphus mauritiana (Indian plum, ber) is one of the most popular lac host trees to culture both the strains (rangeeni and kusmi) of Indian lac insect Kerria lacca (Kerr). A comprehensive and intensive crop surveillance and field collections of insect pests associated with Z. mauritiana trees carried out during the last five years revealed the occurrence of ten new insect pest species viz., Scutellera perplexa (Westwood) (Hemiptera: Scutellaridae); Drosicha sp. (Hemiptera: Margarodidae); Myllocerus dentifer (Fabricius) (Coleoptera: Curculionidae); Amblyrrhinus poricollis Marshall (Coleoptera: Curculionidae); Hypolixus truncatulus Fabricius (Coleoptera: Curculionidae); Peltotrachelus sp. (Coleoptera: Curculionidae); Hypolixus sp. Fabricius (Coleoptera: Curculionidae); Cleonus sp. (Coleoptera: Curculionidae); Leptocentrus narayani (Hemiptera: Membracidae) and Cassida exilis Bohemann (Coleoptera: Chrysomelidae) which are reported for the first time in lac production system from India. Occurrence of Myllocerus discolor Boheman (Coleoptera: Curculionidae) on Z. mauritiana has been reported from other parts of the country but it has been reported for the first time from the state of Jharkhand. Chrysomelid, Oocassida pudibunda (Boheman) (Coleoptera: Chrysomelidae) and membracid Otinotus sp. (Hemiptera: Membracidae) incidence on cultivated trees of Z. mautitiana has been reported from Gujarat. From Jharkhand state, it has been reported for the first time in lac production system. Distribution and occurrence of Xanthochelus faunus Olivier (Coleoptera: Curculionidae) on Z. mauritiana have been reported by various workers from different regions, but its occurrence in lac production system has been reported for the first time from Ranchi, Jharkhand. A number of curculionid species were found to infest this host.

New Record of Insect Pests Attacking Schleichera oleosa: A Commercial Host for Culturing Lac Insect, Kerria lacca (Kerr) from India

Lac is a natural resin of insect origin produced by lac insect, Kerria lacca (Kerr) (Homoptera: Tachardiidae) which finds application in many industrial sectors. Schleichera oleosa (kusum) is one of the major commercial lac hosts for raising kusmi strain of lac insect. Kusmi strain of lac is highly priced in commerce than rangeeni strain due to its superior quality. This host alone is contributing about 35–40 % of the total lac production at national level. In changing climatic scenario, emergences of new insect pest complex is being observed. Comprehensive and intensive host plant surveillance and field collections of insect pests associated with lac host S. oleosa carried out during the last 5 years reveal the occurrence of some new pests for the first time on this specific host. Egyptian cottony cushion scale, Icerya aegyptiaca (Douglas) (Hemiptera: Margarodidae); Scale insect, Aulacaspis sp. (Hemiptera: Diaspididae); Leaf hopper, Amrasca biguttulla (Hemiptera: Cicadellidae); Weevils, Amblyrrhinus poricollis Schoenherr (Coleoptera: Curculionidae) and Peltotrachelus sp. (Coleoptera: Curculionidae); Sweet potato bug, Physomerus grossipes Fabricius (Hemiptera: Coreidae) and soapberry bug, Leptocoris augur (F.) (Hemiptera: Rhopalidae) which have not been recorded earlier in lac production system are hereby reported for the first time from India on S. oleosa. Interestingly some of the insect pests which were reported as minor and sporadic pests by earlier workers have been replaced by another species as the Curculionids attacking on commercial lac hosts. Some of the pests which were of sporadic nature are now becoming a pest of regular occurrence with more severity of damage. Considerable variations in their period of occurrence and activity have also been noticed.

Pigeonpea-Lac insect interaction: Effect of lac culture on grain yield and biochemical parameters in pigeonpea

Present experiment was conducted to know the impact of pigeonpea-lac insect interaction for the production of raw lac/scrapedlac as well as grain yield and protein quality in seeds. On the basis of broodlac and scrapedlac yield, five genotypes of pigeonpea viz., IPA 8–2, Bahar, Assam local, Acc.no. 591139 and RCMP 5 were identified promising for lac production. Rearing of lac insect on pigeonpea reduced 100 seed weight (13.03%) and grain yield per plant (12.08%) significantly but no significant reduction was observed on crude protein content in seeds (1.02%). Biochemical traits measured in mature leaves in inoculated and control plants revealed that reducing sugar (RS), chlorophyll ‘a’ and total chlorophyll decreased after lac insect inoculation but non-reducing sugar, total sugar (TS), proline and malondialdehyde increased after insect inoculation. The biotic stress rendered due to lac insect (free phenol) and abiotic stresses due to high temperature (malondialdehyde) did not significantly affect scrapedlac yield. High chlorophyll components along with high metabolites (RS and TS) supported high scrapedlac yield. Hence, farmers can cultivate lac on this host plant to get good raw lac and grain yield without losing the crude protein quality of grain. The loss in grain yield is compensated by additional income from raw lac. The profit obtained from raw lac along with grain will be much higher than sole crop for grain.

Wood Degradation and Optimized Laccase Production by Resupinate White-Rot Fungi in Northern Thailand

One hundred and thirty samples of resupinate white-rot fungi were collected from natural sites in Northern Thailand during the dry season (October-December) as a bioresource for lignin-degrading enzymes (laccase (Lac), lignin peroxidase (LiP), and manganese peroxidase (MnP)). All 130 isolated fungal strains grew well in potato dextrose broth and produced lignin-degrading enzymes at different levels after 7 days of incubation. The selected resupinate fungi, RCK783S, produced maximum Lac at 4,218 U/L, whereas MnP and LiP activities were detected at relatively low levels in all selected fungal strains. The RCK783S was further identified as a new record of Fibrodontia sp. in Thailand. Response surface methodology (RSM) was applied to evaluate the effect of medium composition, i.e., peptone, glycerol, L-asparagine, and CuSO4, on Lac production by Fibrodontia sp. RCK783S. The experiments showed optimum concentrations of peptone, glycerol, L-asparagine, and CuSO4 at 0.625, 15.00, 2.188, and 0.003 g/L, respectively, to produce the highest Lac concentration of 6,086.01 U/L, a 1.44-fold increase from that in the original medium. In addition, the degradation of Eucalyptus camaldulensis was investigated during the solid-state cultivation of Fibrodontia sp. RCK783S. The results showed that lignin was degraded, with lignin loss being 18% after 30 days, coinciding with the highest released Lac activity.

Effective induction of pblac1 laccase by copper ion in Polyporus brumalis ibrc05015

Polyporus brumalis ibrc05015 is a strain capable of high laccase (Lac) production. Among several inducers, 0.25 mM copper was most effective for Lac production. One of the Lacs induced by copper was PbLac1, and its transcription was induced within 60 min after copper addition. The promoter region of pblac1 contained six putative metal response elements and one Ace1 consensus cis-element. We cloned the P. brumalis PbAce1 transcription factor, a homologue of Saccharomyces cerevisiae transcription factor Ace1, which regulates metallothionein genes in response to excess copper. PbAce1 complemented the function of Ace1 in an S. cerevisiae Δace strain. The conserved N-terminal copper-fist DNA binding domain of PbAce1 was required for complementation. In the PbAce1 complemented Δace1 strain, the pblac1 promoter was constitutively expressed at a high level, independent of copper concentration. PbAce1 has two Cys-rich repeat motifs (PbC1 and PbC2), which are similar to the Cys-rich repeat domain in metallothionein proteins, and are uniquely conserved in the C-terminal domain of basidiomycetous Ace1 sequences. These C-terminal domains could be involved in copper sensing and concentration-dependent Lac production in basidiomycetous fungi.

Optimization of Lignin Peroxidase, Manganese Peroxidase, and Lac Production from Ganoderma lucidum Under Solid State Fermentation of Pineapple Leaf

This study was undertaken to isolate ligninase-producing white-rot fungi for use in the extraction of fibre from pineapple leaf agriwaste. Fifteen fungal strains were isolated from dead tree trunks and leaf litter. Ligninolytic enzymes (lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (Lac)), were produced by solid-state fermentation (SSF) using pineapple leaves as the substrate. Of the isolated strains, the one showing maximum production of ligninolytic enzymes was identified to be Ganoderma lucidum by 18S ribotyping. Single parameter optimization and response surface methodology of different process variables were carried out for enzyme production. Incubation period, agitation, and Tween-80 were identified to be the most significant variables through Plackett-Burman design. These variables were further optimized by Box-Behnken design. The overall maximum yield of ligninolytic enzymes was achieved by experimental analysis under these optimal conditions. Quantitative lignin analysis of pineapple leaves by Klason lignin method showed significant degradation of lignin by Ganoderma lucidum under SSF.

An Analysis of price behaviour of Lac at different levels of market in Jharkhand

A study was undertaken to analyse the price behaviour of lac in terms of trend, seasonality and cycles in important primary and secondary markets of Jharkhand. The secondary data on monthly average prices of lac at primary and secondary markets were collected for a period of 20 years spanning from 1988-1989 to 2007-2008. A positive trend has been shown in prices of both the strains of lac i.e. rangeeni and kusmi lac during the study period which was statistically significant at 1 % probability level for all three levels of market. Growth rate of rangeeni lac prices at growers, assembling centers and manufacturing centers were found to be 9.94, 10.10 and 10.06 % per annum, respectively while for kusmi lac it was 10.13, 10.11 and 10.48 % per annum, respectively. Only one peak of prices have been observed at growers and assembling centers level while two peaks of prices have been observed in case of manufacturing centers for rangeeni lac. For kusmi lac one peak of prices have been observed at growers and manufacturing centers level while two peaks of prices have been observed in case of assembling centers. No regular cycles have been observed in the rangeeni and kusmi lac prices during the study period. Intra year price variation was more at growers and assembling centers level in comparison to manufacturing centers. The seasonality in prices can be reduced by sustained production, production in diverse agro-climatic condition, primary processing of lac at village level and integration of lac production in various lac growing regions of the country.

Growth Analysis of Lac production for the state of Chhattisgarh

Present paper is based on the secondary data on lac production for four years (2006-2007 to 2009-2010). Status of lac production in a lac growing districts of Chhattisgarh has been assessed with parameters like minimum, maximum, average production and Simple Growth Rate. The analysis of data shows that Korba district recorded highest production i.e. 29.5 % of total production of the state followed by Kanker (18.7 %), Rajnandgaon (15.1 %) and others. Only two districts namely Korba and Raipur recorded positive growth to the extent of 9.6 and 4.3 % per annum. Highest negative growth rate was recorded in Durg (-52.3 %) and Sarguja (-50.2 %) districts but their contribution in state production is low. Kanker and Rajnandgaon, the two productive districts producing more than 1000 tons per annum recorded negative growth of 26.1 and 31.8 % per annum. For the state as whole, highest negative growth was recorded for rainy season crop of rangeeni 37.7 % followed by kusmi-summer (-17.5 %), kusmi-winter (-14.3 %) and rangeeni-summer crop (-5.7 %). The present analysis reflects need of better management practice to protect the lac crops from the effects of pest and diseases.

Status of Two Species of Lac Insects in the Genus Kerria from China Based on Morphological, Cellular, and Molecular Evidence

The taxonomic status of the Chinese lac insects Kerria yunnanensis (Ou and Hong) (Hemiptera: Kerridae) and K. ruralis (Wang, Yao, Teiu and Liang) were analyzed in this paper by comparing morphological, cellular, and molecular data. Cladistic analysis showed K. yunnanensis and K. ruralis to be distinct from other Kerria species such as K. lacca and K. chinensis. The karyotype of K. yunnanensis was 3A and the chromosome structure was K = 6m + 2sm + 10T, while in K. ruralis the karyotype was 3B and the chromosome structure was K = 8m + 10T. Kerria ruralis and K. yunnanensis had the closest relationship among species in the genus as they had the most similar karyotype homology. Based on the karyotype analysis, K. sindica and K. lacca formed a sister group with K. ruralis and K. yunnanensis. Kerria pusana and K. nepalensis were clustered as a sister branch, indicating the close relationship of these taxa. The karyotype of K. chinensis was however, different from the other six species and formed a separate branch. RAPD analysis also showed that K. yunnanensis and K. ruralis had distinct differences from other species of Kerria, although they did not form sister taxa. Molecular analysis based on the EF1α gene using ML, MP, and Mr. Bayes' methods indicated that seven species of lac insects cluster in two major groups. In group 1, K. sindica and K. lacca formed a sister clade and were primitive members of the genus. In group 2, K. chinensis formed the earliest diverging branch followed by K. ruralis. Kerria yunnanensis was the next to diverge followed by the cluster containing K. pusana and K. nepalensis. Hybridization testing showed that crosses neither between K. yunnanensis and K. sindica, nor between K. yunnanensis and K. lacca could produce first generation larvae. This was indicative that K. yunnanensis had a distant genetic relationship from the other species. Morphological, cellular, molecular, and hybridization results confirmed the independent status of the Chinese endemic species K. yunnanensis and K. ruralis. Kerria ruralis was genetically closely related to K. yunnanensis, but relatively far from K. lacca. The main commercial species in China was K. yunnanensis, while in Thailand it was K. chinensis. The commercial species in Myanmar included K. nepalensis and K. pusana, the latter being most widely used in lac production.

An analysis of price spread in marketing of lac in Madhya Pradesh

The present paper examines the marketing costs and price spread in marketing of lac in the state of Madhya Pradesh. Two major lac producing districts i.e. Seoni and Balaghat have been selected randomly for the present study. Regarding data collection on marketing costs, margins and constraints in lac marketing, ten of each category viz. lac growers, market functionaries and manufacturers were randomly selected and interviewed during 2005-2006. Primary data have been collected from the respondents with the help of pre-tested schedule. Tabular analysis was used for the present work. The lac grower received Rs. 66 per kg. and the lac grower’s share in consumers price was 76.92 per cent. The primary purchaser received a margin of Rs. 212 per quintal and incurred Rs. 88 per quintal on marketing cost. The total marketing cost paid by the wholesaler was Rs. 1,506 per quintal. The wholesaler’s marketing margin was Rs. 174 per quintal. Arhat charges were 3 per cent of the transacted amount. The study has revealed that there is a tremendous scope to increase the profitability of lac growers in the study area by group marketing, co-operative marketing, establishment of processing units in the lac production catchments, provision of infra structural facility for marketing, strengthening of market extension network and promotion of quality consciousness amongst farmers, traders and manufacturers of lac.

Economics and resource use efficiency of lac cultivation in Jharkhand

The present paper examines the cost, return and resource use efficiency in lac cultivation on major lac host plants. This paper is based on the analysis of data collected on 400 lac growers of Ranchi and West Singhbhum district in the year 2003-2004 and 2004-2005. Primary data was collected from the respondents with the help of pre-tested schedule/questionnaire. Simple tabular and Cobb Douglas production function was used for the present analysis. The total cost of lac cultivation was found to be Rs. 5,132, Rs. 9,347 and Rs. 68,808 per 100 host trees for Palas (Butea monosperma). Ber (Zizyphus mauritiana) and Kusum (Schleichera oleosa), respectively. The high cost of cultivation on Kusum was due to high labour and broodlac requirement. The net return was found to be Rs. 9,772, Rs. 19,543 and Rs. 1,62,837 for Palas, Ber and Kusum, respectively. Analysis of variance indicated that 76.46%, 66.73% and 68.26% variation in total income from lac for Palas, Ber and Kusum, respectively was explained by four variables like number of host utilized, number of human labour days, utilized, amount of broodlac in kg and value of other inputs in Rs.. Out of these human labour days utilized and amount of broodlac inoculated were significant at 5 per cent level of significance in explaining the variation. This showed increase in the level of human labour days utilized and amount of broodlac inoculated resulted in enhancing efficiency of lac cultivation on all the three hosts, contributing significantly towards gross return. Marginal value product analysis suggested a significant scope for increasing lac production at growers level by vertical growth in lac cultivation i.e. increase in production by using more input on the same host.

New and different lignocellulosic materials from Turkey for laccase and manganese peroxidase production by Trametes versicolor

AbstractIn the present study, the production of laccase (Lac) and manganese‐dependent peroxidase (MnP) by the white‐rot fungus Trametes versicolor grown in submerged cultures with different agricultural residues was investigated. The lignocellulosic materials studied were almond shells, hazelnut husks, sunflower stems, clover straw and hazelnut cobs, because they are common agricultural wastes in Turkey. Among the different lignocellulosic materials studied, hazelnut cobs provided the highest Lac and MnP activities (47.09 and 109.21 U/L, respectively). The optimum conditions were determined for Lac and MnP production in submerged cultures of T. versicolor by using hazelnut cobs as substrate. For Lac production, the optimum incubation time, hazelnut cob concentration, pH, and shaking rate were found as 4 days, 2% w/v, 6.0 and 130 rpm, respectively. For MnP production, the optimum incubation time, hazelnut cob concentration, pH and shaking rate were found as 5 days, 2% w/v, 6.0 and 90 rpm, respectively.

Velocidade crítica como um método não invasivo para estimar a velocidade de lactato mínimo no ciclismo

A velocidade de lactato mínimo (VLM) representa o ponto de equilíbrio entre produção e remoção do lactato sanguíneo (lac). Com objetivo de analisar a validade da velocidade crítica (VC) como método não invasivo de estimar a VLM no ciclismo outdoor, 15 ciclistas (67,9 ± 5,7kg; 1,70 ± 0,1m; 26,7 ± 4,2 anos) percorreram as distâncias de 2, 4 e 6km em velódromo no menor tempo possível. A VC foi identificada pelo modelo distância-tempo a partir das combinações de séries preditivas de 2 e 4km (VC2/4), 2 e 6km (VC2/6), 4 e 6km (VC4/6) e 2, 4 e 6km (VC2/4/6). Para identificação da VLM foi realizada uma série de 2km à máxima velocidade, seguida de seis séries incrementais de 2km com 1 minuto de pausa para dosagem de lac. A VLM foi identificada visualmente (VLMv) e aplicando-se função polinomial (VLMp). Não foram observadas diferenças entre VLMv (33,3 ± 2,5km.h¹) e VLMp (33,1 ± 2,6km.h¹). Com exceção da VC4/6 (34,6 ± 3,5km.h¹), os valores de VC2/4 (38,0 ± 2,2km.h¹), VC2/6 (36,1 ± 2,4km.h¹) e VC2/4/6 (36,1 ± 2,5km.h¹) diferiram da VLMp e VLMv. Os autores concluem que, apesar de ser ~1km/h acima da VLM, a VC identificada a partir de séries preditivas de maior duração (4 e 6km - aproximadamente 6 e 10 min) não diferem estatisticamente e apresentam alta correlação e concordância com a VLM. No entanto, é necessário investigar se a VC representa um equilíbrio entre remoção e produção de lac durante exercícios de longa duração no ciclismo outdoor.

Effect of Copper and Manganese Ions on Activities of Laccase and Peroxidases in Three <I>Pleurotus</I> Species Grown on Agricultural Wastes

Copper (Cu2+) and manganese (Mn2+) ions influenced laccase (Lac) and peroxidase production in Pleurotus eryngii, Pleurotus ostreatus, and Pleurotus pulmonarius. In P. eryngii, the optimum Cu2+ concentration for Lac production was 1 mM and for peroxidases 10 mM, and Mn2+ concentration of 5 mM led to peaks of Lac and peroxidase activity. In P. ostreatus HAI 493, the highest level of Lac activity was at Cu2+ concentrations of 1 and 10 mM and Mn2+ concentration of 1 mM, respectively. The absence of Cu2+ and Mn2+ caused the highest levels of peroxidase production. In P. ostreatus HAI 494, the highest level of Lac activity was at a Cu2+ concentration of 5 mM and at Mn2+ concentration of 1 mM, respectively. High levels of peroxidase activity were found in the medium without and with 1 mM Cu2+, and at 1 and 5 mM Mn2+, respectively. In P. pulmonarius, the highest Lac activity was found in the presence of 5 mM Cu2+ and 5 mM Mn2+, respectively. The absence of Cu2+ and Mn2+ as well as their presence at a concentration of 1 mM led to the peaks of peroxidase activities.

Ability of industrial dyes decolorization and ligninolytic enzymes production by different Pleurotus species with special attention on Pleurotus calyptratus, strain CCBAS 461

Eight different Pleurotus species were tested for their Orange G and Remazol Brilliant Blue R (RBBR) decolorization capacity and their ligninolytic properties. All the species produced laccase (Lac) and manganese peroxidase (MnP) and in five species we found aryl-alcohol oxidase (AAO) activity. Strain CCBAS 461 of a very little studied species Pleurotus calyptratus was chosen for a more detailed study. This strain produced a relatively high amount of Lac, MnP and also AAO. Within 14 days the strain decolorized up to 91% of Orange G and 85% of RBBR in liquid culture and more than 50% of these dyes on agar plates. P. calyptratus is able to decolorize efficiently also other azo and phthalocyanine dyes, but only a limited decolorization capacity was found in the case of polyaromatic and triphenylmethane dyes. Lac and MnP production was strongly influenced by the kind of cultivation media and by the dye present.

Autochthonous fungal strains with high ligninolytic activities from Tunisian biotopes

This work represents the first report on the ability of autochthonous fungi of Tunisia to produce ligninolytic enzymes. Three hundred fifteen fungal strains were isolated from different Tunisian biotopes. These fungal strains were first screened for lignin-modifying enzymes on solid media containing Poly R-478 or ABTS. Of the 315 tested strains, 49 exhibited significant ABTS-oxidation activity, expressed within the first week of incubation and only 18 strains decolourised the Poly R-478. These positive strains were further screened in liquid culture and laccase, and lignin and Mn 2+ -oxidizing peroxidases activities were assayed. Of the 67 strains grown on liquid medium, 28 produced at least one of these 3 enzymes. The 8 highest producers of ligninolytic activities were identified by molecular techniques and 3 among them produced Lac, MnP and LiP simultaneously. New isolates reported in this work as fungi with significant ligninolytic activities includes Oxyporus, Stereum and Trichoderma. The isolated Trametes trogii CTM 10156 was the best Lac producer. Culture conditions and medium composition were optimised for this strain and resulted in high Lac production of 110 U ml -1 within 15 days of incubation (367 times higher than control medium). African Journal of Biotechnology Vol. 4 (5), pp. 431-436, 2005

Ligninolytic enzyme production in Pleurotus eryngii depending on the medium composition and cultivation conditions

Pleurotus eryngii produced laccase (Lac) both under conditions of submerged fermentation (SF) and solid-state fermentation (SSF) using all of the investigated carbon and nitrogen sources, while significant peroxidases production occurred only under SSF conditions. The highest levels of Lac activity were found under SF conditions of dry ground mandarine peels (999.5 U/l). After purification of extracellular crude enzyme mixture of P. eryngii which was grown under SF conditions with dry ground mandarine peels it was revealed two peaks of Lac activity and one peak of activity against phenol red in absence of external Mn2+ which was very low (1.4 U/l). Results obtained by purification also showed that the levels of phenol red oxidation in absence of external Mn2+ were higher than phenol red oxidation levels in presence of external Mn2+. In the medium with the best carbon source for Lac production (dry ground mandarine peels), (NH4)2SO4, with a nitrogen concentration of 20 mM, was the most optimum nitrogen source among 8 investigated sources.

Production of Ligninolytic Enzymes by Oyster Mushroom Pleurotus ostreatus (Jacq.:Fr.) P. Kumm. Under Different Nutritional Conditions

One of the effective methods for regulating and increasing the quantity of ligninolytic enzymes is the addition of the appropriate inducers to the nutrient medium. The ligninolytic enzymes of some white-rot fungi are synthesized only after the primary growth phase in response to nitrogen and carbon limitations in the medium. In the screening program, Pleurotus ostreatus appeared to be one of the best producers of extracellular laccase (Lac) and manganese peroxidase (MgP). Therefore, we compared the effect of different carbon and nitrogen sources, including lignocellulosic substrates, on P. ostreatus 98 oxidative enzyme production.The secretion of Lac, MgP, and versatile peroxidase (VP) were significantly dependent on 11 types of carbon sources when species were grown in a medium with 2 g/L NH4NO3. Mandarin peels, which were used as one of the possible substrates, ensured very high yields of Lac (2375.5 U/L). Increasing its concentration in the nutrition medium from 20 g/L to 40 g/L resulted in a more than six-fold increase in Lac activity. Carboxylmethylcellulose, gluconic acid, glucose, and cellobiose (10 g/L) appeared to be poor growth substrates for Lac production. Moreover, results of this study showed that the activity of the enzyme was at its lowest level on medium containing avicel and mannitol.Lignin degradation of P. ostreatus 98 on culture media with 10 g/L glucose and 11 types of nitrogen sources (0.5 g/L) was suppressed. This species showed high Lac activity in the presence of peptone, kazein acid, and corn step liquor (887.1 U/L, 802.3 U/L, and 674.3 U/L, respectively). In contrast, medium with NaNO3 NH4NO3, and (NH4)2SO4 inhibited this enzyme accumulation.Secretion of VP and MnP by the investigated strain was comparatively low. Adding different carbon sources to the medium caused variation of VP activity from 0.24 U/L (medium with xylan) to 32.4 U/L (medium with mandarine peels). The results demonstrated that MnP activity was almost two-fold lower than VP activity on all of the used sources. The content of kazein acid and corn step liquor exerted the most favorable influence on the activity of VP and MnP. On the other hand, NH4NO3, NH4Cl, and (NH4)2SO4 were rather poor nitrogen sources for the production of these peroxidases.In conclusion, it was shown that the synthesis of Lac, MnP, and VP by P. ostreatus 98 differed in various nutritional conditions. Among the different carbon and nitrogen sources, mandarine peels and peptone were optimal substrates for high production of the investigated enzymes.