Laboratory simulated dissipation of metsulfuron methyl and chlorimuron ethyl in soils and their residual fate in rice, wheat and soybean at harvest

Two sulfonylurea herbicides, metsulfuron methyl （Ally 20 WP） and chlorimuron ethyl （Classic 25 WP） were evaluated for their dissipation bchaviour in alluvial, coastal saline and laterite soils under laboratory incubated condition at 60% water holding capacity of soils and 30 ℃ temperature was maintained. In field study herbicides were applied twice for the control of grasses, annual and perennials broad leaves weeds and sedges in rice, wheat and soybean to find out the residual fate of both the herbicides on different matrices of respective crops after harvest. Extraction and clean up methodologies for the herbicides were standardized and subsequently analyzed by HPLC. The study revealed that the half-lives of metsulfuron methyl and chlorimuron ethyl ranged from 10.75 to 13.94 d irrespective of soils and doses applied. Field trials with rice, wheat and soybean also revealed that these two herbicides could safely be recommended for application as no residues were detected in the harvest samples.

Production of chitinolytic enzymes with Trichoderma longibrachiatum IMI 92027 in solid substrate fermentation

Thirty Trichoderma strains representing 15 species within the genus have been screened for extracellular production of chitinolytic enzymes in solid substrate fermentation (SSF). T.longibrachiatum IMI 92027 (=ATCC 36838) gave the highest yield (5.0 IU/g dry matter of substrate) after 3 days of fermentation on wheat bran-crude chitin (9:1 mixture) medium. The optimum moisture content (66.7%), chitin content (20%), initial pH of the medium (2-5) and time course (5 d) of SSF were determined for strain IMI 92027. No significant effect of different N and P additives was found on the chitinase yield in wheat bran-chitin mixture medium. Cellulase, xylanase, alpha-amylase and beta-xylosidase activities were also detected. The pH and temperature optima of chitinase complex of T.longibrachiatum IMI 92027 was found to be at 4.5 and 55 ℃, respectively. The enzyme totally lost its activity at 70 ℃ in 5 min in the absence of the substrate but retained about 15% of its initial activity even at 70 ℃ after incubation of 60 min in the presence of SSF solids (residual substrate and fungal mycelium). Purification of protein extract from the SSF material revealed high chitinolytic activities between pI 5.9.-4.8 where N-acetyl-β-D-hexosaminidase and chitinase peaks have been found in the same pI range. Chitinase peaks could be described at least at four pI values: pI 5.9; 5.6; 5.3 and 4.8 while at least four main N-acetyl-β-D-hexosaminidase peaks could be separated at pI 6.0 and 5.1 and at more basic isoelectric points of 7.2 and 8.0. Two chitinases with 43.5 kDa and 30 kDa were purified at acidic isoelectric point.

Selection of Trichoderma mutants with enhanced cellulase production and resistant to catabolite repression

Due to high cost and relatively low efficiency of cellulase enzymes used for the saccharification of pretreated lignocelluloses, the improvement of cellulase secreting microorganisms is of vital importance. Trichoderma reesei QM 6a, an excellent source of cellulase was selected in the late 1960’s. at Natick Laboratories by its performance on pure cellulose (Solka Floc, Avicel) . QM 6a is the wild parent strain of best existing hypercellulolytic mutants such as Rut C30, VTT-D-80133, L27, CL-847 and others. Utilization of cheaper carbon sources (e.g., pretreated wood or straw) both in enzyme production and in hydrolysis necessitates to investigate fungal species other than T.reesei. A screening program was initiated to test 150 wild-type Trichoderma strains in shake flask for cellulase production on SO 2-impregnated and steam pretreated spruce and willow, candidate substrates for bioalcohol program in Sweden. Filter paper activity (FPA) method was used to determine the overall cellulase activity. Strain TUB F-1505 was selected as promising candidate for mutagenesis. This wild strain was isolated from a tropical rain forest area near Manaus, Brazil. Isolate F-1505 was subjected to NTG-mutation to select catabolite (glucose, glycerol) resistant mutants. A Petri plate clearing assay using Walseth cellulose, glycerol or glucose and Triton X100 (colony size inhibitor) was applied for pre-screening of the colonies. Over 6000 colonies were evaluated. Best colonies were tested in shake flask fermentation on pretreated spruce and willow as carbon sources. Mutants producing higher levels of cellulase (FPA) were further mutated by either NTG or UV-light. At least 4 mutants were obtained and freeze-dried exhibiting equivalent or higher cellulase production as compared to Trichoderma reesei Rut C30.

Trichoderma spp. capable of growing at low temperatures with biocontrol potential

@Szakacs G$Technical University of Budapest, Department of Agricultural Chemical Technology, 1111 Budapest, Gellert ter 4, Hungar@Tavaszi A$Technical University of Budapest, Department of Agricultural Chemical Technology, 1111 Budapest, Gellert ter 4,

Production of chitinases with Trichoderma harzianum isolates using solid substrate fermentation

Over forty Trichoderma harzianum isolates have been screened in solid substrate fermentation (SSF) for chitinase production. Strains were isolated from Asian soil and tree bark samples. Identification was performed in Canada and Austria by classical and molecular taxonomical methods. Four SSF media were used for the screening. They contained wheat bran, crude chitin from crab shells (SIGMA) and different salt solutions for wetting of the substrate. In a five day fermentation at 30°C the best chitinase producers were T. harzianum TUB F-691, TUB F-693, TUB F-699, TUB F-700, TUB F-927, TUB F-947 and TUB F-972 isolates (TUB = Technical University of Budapest culture collection) . The best producers yielded between 3.5-5.5 International Unit/g dry matter (DM) chitinase. T. harzianum TUB F-947 was selected for further optimization. This strain was isolated from a soil of Thailand. The optimum moisture content (67%), optimal alternative substrate-carrier for SSF (wheat straw) and chitin content of the substrate (30%) were determined. Temperature and pH optima of chitinase produced by T. harzianum TUB F-947 were found to be at 50°C and 5.0, respectively. The enzyme complex was thermally not stable at 50 ℃. Medium optimization experiments to enhance the chitinase production using statistical methods also have been performed.

Biodiversity of Trichoderma spp. in TUB culture collection

Culture collection of the Technical University of Budapest (TUB) comprises app ro x. 2800 microorganisms with special emphasis on lignocellulose degrading fungi a nd actinomycetes. For isolation and screening programs, 460 soils are stored at +5 ℃. They were collected in 58 countries, including extreme environments. There are 860 Trichoderma strains in TUB collection, representing 45 count ries and 173 soils and/or tree barks as isolation sources. Trichoderma spp . selected from soils in the tundra region (Rocky Mountains, Colorado) grow at l ow temperatures such as 5-10 ℃. These strains practically do not grow at 30 ℃ . On the contrary, many Trichoderma strains were isolated from tropical or s ubtropical soils and decaying plant materials at 35-40 ℃ in Brazil, Peru, Cost a Rica, Guatemala, Hawaii, Tanzania, Thailand and Indonesia. Trichoderma str ains tolerating limited oxygen supply were selected from river muds and sediment s. Trichoderma spp. tolerating or partially degrading 2,4-dichlorophenol a nd 2,4,6-trichlorophenol in 20 mg/kg concentration were selected from polluted soils. As a part of an attempt to assess the global biodiversity of Trichoderma, researchers of Technical University of Vienna and Agriculture Canada, in collab oration with TUB collection, identified and characterized seven new assumed taxa of Trichoderma from Eurasia.

Enzymes of Trichoderma and other origin in biopreparation of cotton

Preparation and bleaching are among the most energy and chemical intensive steps of the traditional cotton finishing. About 75% of the organic pollutants arising from textile finishing are derived from the preparation of cotton goods. Biopreparation may be a valuable and environmentally friendly alternative to harsh alkaline chemicals for preparing of cotton. Different enzymes i.e. cellulases, pectinases, lipases and proteases have been tested for biopreparation. Many papers have been published how enzymes effect on the properties of cotton fabrics in respect to their effectiveness to replace alkaline scouring and how enzymes modify the various cell wall components of cotton fibers. However, very few data have been reported on bleachability and dyeing behavior of the bioscoured fabrics. In this work an acidic cellulase (Celluclast 1.5 L, Trichoderma reesei origin), an acidic pectinase-hemicellulase (Viscozyme 120 L , Aspergillus aculeatus) and a cellulase-free xylanase (Pulpzyme HC, Bacillus sp.) enzymes were used for bioscouring of greige cotton fabric. Selected properties of the pretreated samples, which are important for effective dyeing, are characterized in detail. Effect of hydrogen peroxide bleaching, applied subsequent to the biopretreatment on the bleachability and dyeing properties of the samples is also elucidated. A reactive dye was used at four different concentrations to compare the dyeing behavior of biopretreated as well as biopretreated and subsequently bleached cotton fabrics with that of the alkaline scoured as well as alkaline scoured and bleached fabrics, respectively. Color evenness and uniformity, and wash fastness properties of the dyed samples are also determined [1]..

Imidacloprid in processed tea and tea liquor

Imidacloprid is a newly introduced broad-spectrum chloronicotinyl insecticide and will find its way in agricultural production, particularly in Asia. However, information on the fate of imidacloprid in crop plants is lacking. The degradation of imidaclopnd in processed CTC tea and tea liquor was investigated in the present study in which imidacloprid was applied at recommended application rate （30.0 g a.i./ha） and twice the recommended application rate （60.0 g a.i./ha） for three consecutive seasons. Imidacloprid was rapidly dissipated in processed tea following first order reaction kinetics at all application rates and had half-lives of 0.9 1-1.16 d with the residue in tea liquor found to be below detectable limit on 3rd day samples. The study revealed that imidacloprid is safe for human consumption and will not pose any residual toxicity problem.

Are mycoparasitism and chitinase production species or isolate dependent in Trichoderma?

The relationship between taxonomic status of Trichoderma spp., chitinase production in solid substrate fermentation (SSF) on four media and mycoparasitism in dual culture (confrontation assay) against four plant pathogenic fungi was studied. Seventy five Trichoderma isolates belonging to 35 species have been screened. The plant pathogenic fungi used in confrontation assay were Botrytis cinerea, Fusarium oxysporum f.sp. dianthi, Rhizoctonia solani and Sclerotinia sclerotiorum . The SSF media contained wheat bran, crude chitin (from crab shells, SIGMA) and salt solutions. The best performing isolates in mycoparasitism tests were Trichoderma flavofuscum, T.harzianum, T.inhamatum, T.koningii and T.strigosum. Some isolates exhibiting good mycoparasitism produced chitinase in SSF only at low or medium level. In contrary there were isolates with excellent extracellular chitinase production but their biocontrol potential did not belong to the leading group. Statistical methods have been used to evaluate the data.

Xylanase production by Trichoderma strains in solid substrate fermentation

The importance of microbial enzymes in pulp and paper manufacturing has grown significantly in the last two decades. Solid substrate fermentation (SSF) holds tremendous potential for the production of microbial enzymes of commercial interest. SSF can be of special interest in those processes where the crude fermented product (whole SSF culture, in situ enzyme) may be used directly as the enzyme source. Xylanase preparations practically free of cellulase activity are especially useful for biobleaching of crude cellulose pulps. Thirty-nine Trichoderma isolates have been screened in SSF for xylanase production on hardwood oxygen-delignified soda-aq pulp as carbon source and enzyme inducer. Xylanase activities varied between 0 and 2200 IU/g dry matter (DM) of initial substrate. In most instances, the simultaneously produced cellulase levels were below 1.0 Filter Paper Unit (FPU) /g DM. The xylanase to cellulase activity ratio varied in the range of 5 to 3500. The three most promising isolates (TUB F-1647, TUB F-1658 and TUB F-1684) yielded xylanase activity of 2040, 1300 and 1500 IU/g DM xylanase, respectively, and 0.64, 0.43 and 0.43 FPU/g DM cellulase with a xylanase to cellulase activity ratio of 3200, 3000 and 3500, respectively. Wild strains F-1647, F-1658 and F-1684 were isolated from tree bark of Maldives, soils of Peru (last two), respectively. Medium optimization experiments to enhance the xylanase yield and to increase the xylanase to cellulase ratio have also been performed.

Utilization of biodiesel waste in the development of botanical-based floating tablet formulation against early stages of mosquitoes

The current paper has elaborated the efficient utilization of liquid biodiesel waste in combination with dillapiole and citronella essential oil as active ingredients.Sawdust,cellulose and hydrophobic silica were used as inert ingredients,which make the tablet to float over the water surface.ATR-FTIR analysis of tablet confirmed the compatibility with citronella oil,dillapiole,liquid biodiesel waste in tablet composition after compression.Physico-chemical analysis studies show that tablet parameters are in standard limits.SEM analysis shows some porous structures in tablet composition which confirms the floating nature of the tablets.The specific ratio(2:2:1)of citronella oil,dillapiole and liquid biodiesel waste showed maximum mortality,i.e.95%after 24 h.After application,the tablet is nontoxic towards the aquatic organisms and water quality remains unaf-fected.The better performance of the tablets has been evaluated in terms of characterization studies,viz.ATR-FTIR and SEM studies and bioefficacy trials which confirmed the presence of active ingredients responsible for insecticidal activity.