Relationship of pectic enzyme of macrophomina phaseoli with stem-rot disease and retting of jute

Summary Culture filtrates of three strains ofM. phaseoli were found to have pectic enzymes which macerated potato discs and separated the fibre strands of jute stem, but were not toxic. The filtrates with this principle also caused, under controlled conditions, defoliation and wilting of jute plants which are the symptoms of the stem-rot disease.The pectic enzyme contained in the strain MP-C was found to be more virulent in causing the disease and more effective in retting Jute. Thus a relationship of pectic enzyme ofM. phaseoli with stemrot disease and retting of jute has been indicated.Microbiologist, Assistant Biochemist, Research Assistant and Director, respectively.     

Bacterial Population Structure of the Jute-Retting Environment

Jute is one of the most versatile bast fibers obtained through the process of retting, which is a result of decomposition of stalks by the indigenous microflora. However, bacterial communities associated with the retting of jute are not well characterized. To investigate the presence of microorganisms during the process of jute retting, full-cycle rRNA approach was followed, and two 16S rRNA gene libraries, from jute-retting locations of Krishnanagar and Barrackpore, were constructed. Phylotypes affiliating to seven bacterial divisions were identified in both libraries. The bulk of clones came from Proteobacteria ( approximately 37, 41%) and a comparatively smaller proportion of clones from the divisions-Firmicutes ( approximately 11, 12%), Cytophaga-Flexibacter-Bacteroidetes group (CFB; approximately 9, 7%), Verrucomicrobia ( approximately 6, 5%), Acidobacteria ( approximately 4, 5%), Chlorobiales ( approximately 5, 5%), and Actinobacteria ( approximately 4, 2%) were identified. Percent coverage value and diversity estimations of phylotype richness, Shannon-Weiner index, and evenness confirmed the diverse nature of both the libraries. Evaluation of the retting waters by whole cell rRNA-targeted flourescent in situ hybridization, as detected by domain- and group-specific probes, we observed a considerable dominance of the beta-Proteobacteria (25.9%) along with the CFB group (24.4%). In addition, 32 bacterial species were isolated on culture media from the two retting environments and identified by 16S rDNA analysis, confirming the presence of phyla, Proteobacteria ( approximately 47%), Firmicutes ( approximately 22%), CFB group ( approximately 19%), and Actinobacteria ( approximately 13%) in the retting niche. Thus, our study presents the first quantification of the dominant and diverse bacterial phylotypes in the retting ponds, which will further help in improving the retting efficiency, and hence the fiber quality.     

Investigation of the bacterial retting community of kenaf (Hibiscus cannabinus) under different conditions using next-generation semiconductor sequencing

The microbial communities associated with kenaf (Hibiscus cannabinus) plant fibers during retting were determined in an effort to identify possible means of accelerating this process for industrial scale-up. Microbial communities were identified by semiconductor sequencing of 16S rRNA gene amplicons from DNA harvested from plant-surface associated samples and analyzed using an Ion Torrent PGM. The communities were sampled after 96 h from each of three different conditions, including amendments with pond water, sterilized pond water, or with a mixture of pectinolytic bacterial isolates. Additionally, plants from two different sources and having different pretreatment conditions were compared. We report that the best retting communities are dominated by members of the order Clostridiales. These bacteria appear to be naturally associated with the plant material, although slight variations between source materials were found. Additionally, heavy inoculations of pectinolytic bacteria established themselves and in addition their presence facilitated the rapid dominance of the original plant-associated Clostridiales. These data suggest that members of the order Clostridiales dominate the community and are most closely associated with efficient and effective retting. The results further suggest that establishment of the community structure is first driven by the switch to anaerobic conditions, and subsequently by possible competition for nitrogen. These findings reveal important bacterial groups involved in fiber retting, and suggest mechanisms for the manipulation of the community and retting efficiency by modifying nutrient availability.     

The retting of flax after preservation with sulphur dioxide

Experiments were carried out to compare the retting of moist flax preserved with sulphur dioxide with that of green dried flax, using whole straw samples. When retted in water at either a constant 20°C or 28°C dried flax was fully retted after 15 and 10 days respectively whereas the sulphur dioxide treated flax (20 g sulphur dioxide kg“¹ flax DM) had undergone almost no retting after 20 days at 20dC or 10 days at 28°C. Pre-soaking the treated flax for 24 h in water and changing the acidified water, raised the pH of the retting liquor to a more normal value but did not significantly increase the rate of retting. Addition of the pectinase enzyme preparation ‘Flaxzyme’ to retting liquor at the rate of either 1.5 g kg^-1 or 3.0 g kg^-1 water, and at a constant temperature of 20°C, substantially increased the rate of retting of both sulphur dioxide treated and dried flax. Optimum degree of retting was achieved at 24 h with the treated flax and at 97 h with the dried flax. Pre-rinsing of the sulphur dioxide treated straw only served to reduce the rate of retting. It was concluded that natural water retting of sulphur dioxide treated flax is retarded by the presence of acidic residues of sulphur dioxide, while enzyme retting is enhanced by these. In further smaller scale experiments using bundles of cut flax straw Flaxzyme was added at concentrations ranging from 0–8.0 ml litre ¹ to containers containing flax in water at ratios from 1:10 to 1: 600 flax:water and the producion of galacturonic acid was used as an indicator of retting progress. Retting took place more rapidly at higher flax to water ratios for a given enzyme concentration. This effect was attributed to the lower pH of higher flax to water ratios which created pH conditions closer to the pH optimum for the retting enzymes. When enzyme retting was compared at a range of buffered pH's the optimum was pH 4.0. At a buffered pH of 4.0 and a temperature of 19°C, retting of sulphur dioxide treated moist flax (flax to water ratio of 1:10) was achieved with Flaxzyme concentrations as low as 0.5 ml litre”‘,much lower than the previously reported minimum of 3.0 ml litre’.     

Study on microbe retting of kenaf fiber

Retting is the predominant problem in the application of kenaf fiber in high-grade products. While the traditional retting method is water retting, that is, the harvested bast kenaf is immersed in natural water (rivers or tanks) in which indigenous bacteria colonize noncellulosic materials in an anaerobic process resulting in severe environmental problems and low-grade fiber, therefore it is inevitable to seek for a pollution-free or little-pollution retting method. With the more application of biotechnology in textile industry, the more biology-treatments have been researched recently. So microbe retting was employed in this work. The fungus strain was isolated from the river in which kenaf fiber was retted, then microbe retting was performed with this fungus. Substrate species, the initial pH of the culture medium, cultivation temperature, retting time and inoculum size are involved in the experiments and the evaluation of retting is based on the residual gum content in retted kenaf fiber. As a result, the removal of pectin in microbe retting of kenaf is 91.31% under the optimal retting conditions. In addition, the effective retting fungus is also observed with microscope as one kind of filamentous epiphyte.     

Drastic changes in lake ecosystem development as a consequence of flax retting: a multiproxy palaeolimnological study of Lake Kooraste Linajärv,Estonia

This study demonstrates the power of multiproxy palaeolimnological analyses in investigating environmental changes in the Lake Kooraste Linajärv ecosystem through historical time in response to flax retting. Flax retting history was proven by applying pollen and macrofossil evidence and by using several biotic and geochemical proxies on a sediment core. Continuous findings of flax pollen and macrofossil remains in lake sediments were considered as strong evidence for the occurrence of retting. Analyses of the well-dated sediment core show the consequences of flax retting in the lake. As a result, the once clear soft water oligotrophic endorheic lake with limited sedimentation has turned into a hypertrophic high-sedimentation lake with anoxic bottom water, strong stratification and intense water blooms. Despite the fact that flax retting was forbidden in Estonia around ad 1950s and retting has not occurred over the last six decades, anthropogenic alterations were so pervasive in the past, that they have prevented any lake water improvements until the present-day.     

亚麻微生物脱胶菌种的筛选与鉴定

在研究天然水沤法脱胶的过程中,通过初筛、复筛,从沤麻主生物期的沤麻液中筛选出两株茵落周围产生透明圈较大、脱胶酶活较高的菌株。通过形态观察,并对其多项生理、生化指标进行了分析研究,初步鉴定并命名为枯草芽孢杆菌A1和B1。初步加茵脱胶实验表明：枯草芽孢杆菌A1产生果胶酶、木聚糖酶,而不产生纤维素酶,脱胶周期为72小时;枯草芽孢杆茵B1产生果胶酶、木聚糖酶和纤维素酶,脱胶周期为50小时。     

Green bioprocess of degumming of jute fibers and bioscouring of cotton fabric by recombinant pectin methylesterase and pectate lyases from Clostridium thermocellum

Enzymatic processes are emerging as important green biotechnological processes in textile industry. The application of recombinant pectin methylesterase (CtPME) and pectate lyase (CtPL1B) from Clostridium thermocellum for enzymatic degumming of jute or bioscouring of cotton was evaluated. The effectiveness of processes by combination of two enzymes were evaluated that effective degumming of jute and bioscouring of cotton as compared with individual enzyme. The optimum concentrations of two enzymes mixture for both processes, degumming of jute and bio scouring of cotton were 5 mg/mL (2.1 U/mL) of CtPME and 5 mg/mL (3.0 U/mL) of CtPL1B under optimized conditions of 60 min, 100 rpm and 50 °C. FESEM images showed more effective removal of pectin from jute fiber and cotton fabric by enzyme mixture, nevertheless similar to NaOH treatment. Wettability analysis showed mixture of enzymes and NaOH treated cotton fabric absorbed a water drop in 10 s and 8 s, respectively. UTM analysis showed higher tensile strength and Young’s modulus for jute fiber and cotton fabric treated with enzyme mixture than untreated and were similar to those of NaOH treated. These results showed that the CtPME and CtPL1B mixture can be used for replacing the chemical process by green bioprocess in textile industry.     

Retting of Flax by Aspergillus niger

In this study, retting was carried out by Aspergillus niger. The pH, galacturonic acid (GA), and total reducing sugar were determined; the end point was identified by the classic empirical processes and by the maximal GA content of the retting water. The process gave clear and resistent fibers, and the retting time was similar to that of current industrial processes with bacterial enzymes. Control of total acidity was not required, since the pH remained close to neutrality throughout the entire process.     

Use of jute processing wastes for treatment of wastewater contaminated with dye and other organics

A study was conducted to examine the potential of jute processing waste (JPW) for the treatment of wastewater contaminated with dye and other organics generated from various activities associated with jute cultivation and fibre production. Adsorption studies in batch mode have been conducted using dye solution as an adsorbate and JPW as an adsorbent. A comparative adsorption study was made with standard adsorbents such as powdered and granular activated carbon (PAC and GAC, respectively). A maximum removal of 81.7% was obtained with methylene blue dye using JPW as compared to 61% using PAC and 40% using GAC under similar conditions. The adsorption potential of JPW was observed to be dependent on various parameters such as type of dye, initial dye concentration, pH and dosage of adsorbent. The batch sorption data conformed well to the Langmuir and Freundlich isotherms. However, lower BOD (33.3%) and COD (13.8%) removal from retting effluent was observed using JPW as compared to 75.6% BOD removal and 71.1% COD removal obtained with GAC.     

Genetic Structure and Relationship Analysis of an Association Population in Jute (Corchorus spp.) Evaluated by SSR Markers

Population structure and relationship analysis is of great importance in the germplasm utilization and association mapping. Jute, comprised of white jute (C. capsularis L) and dark jute (C. olitorius L), is second to cotton in its commercial significance in the world. Here, we assessed the genetic structure and relationship in a panel of 159 jute accessions from 11 countries and regions using 63 SSRs. The structure analysis divided the 159 jute accessions from white and dark jute into Co and Cc group, further into Co1, Co2, Cc1 and Cc2 subgroups. Out of Cc1 subgroup, 81 accessions were from China and the remaining 10 accessions were from India (2), Japan (5), Thailand, Vietnam (2) and Pakistan (1). Out of Cc2 subgroup, 35 accessions were from China, and the remaining 3 accessions were from India, Pakistan and Thailand respectively. It can be inferred that the genetic background of these jute accessions was not always correlative with their geographical regions. Similar results were found in Co1 and Co2 subgroups. Analysis of molecular variance revealed 81% molecular variation between groups but it was low (19%) within subgroups, which further confirmed the genetic differentiation between the two groups. The genetic relationship analysis showed that the most diverse genotypes were Maliyeshengchangguo and Changguozhongyueyin in dark jute, BZ-2-2, Aidianyehuangma, Yangjuchiyuanguo, Zijinhuangma and Jute 179 in white jute, which could be used as the potential parents in breeding programs for jute improvement. These results would be very useful for association studies and breeding in jute.     

Characterization of a lignified secondary phloem fibre-deficient mutant of jute (Corchorus capsularis)

BACKGROUND AND AIMS: High lignin content of lignocellulose jute fibre does not favour its utilization in making finer fabrics and other value-added products. To aid the development of low-lignin jute fibre, this study aimed to identify a phloem fibre mutant with reduced lignin. METHODS: An x-ray-induced mutant line (CMU) of jute (Corchorus capsularis) was morphologically evaluated and the accession (CMU 013) with the most undulated phenotype was compared with its normal parent (JRC 212) for its growth, secondary fibre development and lignification of the fibre cell wall. KEY RESULTS: The normal and mutant plants showed similar leaf photosynthetic rates. The mutant grew more slowly, had shorter internodes and yielded much less fibre after retting. The fibre of the mutant contained 50 % less lignin but comparatively more cellulose than that of the normal type. Differentiation of primary and secondary vascular tissues throughout the CMU 013 stem was regular but it did not have secondary phloem fibre bundles as in JRC 212. Instead, a few thin-walled, less lignified fibre cells formed uni- or biseriate radial rows within the phloem wedges of the middle stem. The lower and earliest developed part of the mutant stem had no lignified fibre cells. This developmental deficiency in lignification of fibre cells was correlated to a similar deficiency in phenylalanine ammonia lyase activity, but not peroxidase activity, in the bark tissue along the stem axis. In spite of severe reduction in lignin synthesis in the phloem cells this mutant functioned normally and bred true. CONCLUSIONS: In view of the observations made, the mutant is designated as deficient lignified phloem fibre (dlpf). This mutant may be utilized to engineer low-lignin jute fibre strains and may also serve as a model to study the positional information that coordinates secondary wall thickening of fibre cells.     

A comparative performance evaluation of jute and eggshell matrices to immobilize pancreatic lipase

A pancreatic lipase was immobilized on readily available and inexpensive jute and eggshell matrices. The purity of extracted enzyme was confirmed by SDS-PAGE. The maximum protein load for eggshell was 10.23 mg/g, and for jute, it was 5.7 mg/g. The free enzyme activity retention was greater than 80% for eggshell and 43% for jute. The immobilized lipase was stable over a pH range from 7 to 8 for eggshell and 7.5 to 8.5 for jute with over a temperature range from 25 to 45 °C for eggshell and 37 to 40 °C for the jute. FTIR data indicated new bonds on the jute upon immobilization. Although no new bond was observed, immobilization data on eggshell fit well with the Langmuir adsorption isotherm model. The model constants, Γ_max and K_l, were 13.92 mg/g and 0.382 mL/mg, respectively. Mixed adsorption with both ionic and hydrophobic interactions was observed. Lipase adsorption was reduced significantly in presence of Tween 80, whereas the effect was less in case of ionic strength, pH and temperature. For both matrices, scanning electron microscopy (SEM) was used to demonstrate the changes in surface morphology after immobilization. The performance of eggshell was better than that of jute as a matrix for immobilizing pancreatic lipase.     

Potential of Lariophagus distinguendus (Förster) (Hymenoptera: Pteromalidae) to suppress the maize weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) in bagged and bulk stored maize

Grains are often stored in jute bags in developing countries, especially in Africa, as well as in small quantities in bulk. Parasitoids suitable for biological control of stored-product pests should be able to find their hosts in bulk grain or in jute bags over a certain distance in a warehouse containing stacks of bagged grain. The potential of using Lariophagus distinguendus for the biological control of Sitophilus zeamais was assessed in maize stored in jute bags and bulk grain. The ability of the parasitoid to penetrate the jute cloth and the grain mass and parasitize its host was studied under controlled conditions of 25 ± 1 °C and 65 ± 5% RH. Experiments were carried out in small 5-kg jute bags containing 28 d old S. zeamais larvae within infested maize kernels, and in cylinders filled with maize grains and containing caged hosts at different depths. L. distinguendus parasitized S. zeamais in the jute bags and in the storage cylinders at various depths. In the jute bag experiment, out of the 60 L. distinguendus adults released, a mean ± SD of 7.03 ± 1.78% and 6.34 ± 1.01% of the 40 females and of the 20 males released, respectively, entered the jute bags. Significantly, no differences were found between the female and male L. distinguendus that entered the bags. Mean reduction of S. zeamais in the jute bags by parasitoids was 81%. The parasitic wasps also significantly reduced the emergence of S. zeamais in bulk maize. At depths of 20–45 cm from the grain surface, mean reduction of S. zeamais was 74%, while from 95 to 100 cm, mean reduction was 34%. When results from depths lower than 50 cm were pooled and compared with pooled data from depths higher than 90 cm, there was a significant reduction in parasitism at depths of more than 90 cm. For depths below 50 cm a mean of 5.3 L. distinguendus adult offspring per cage emerged compared with a mean of 2.6 at depths of more than 90 cm. These results support the approach to utilize L. distinguendus as a component in the integrated control of S. zeamais in bagged or bulk stored maize.     

Effect of lipid monolayers on diffusion of oxygen through the air/water interface

The dependence of the diffusion current on the depth of immersion of the electrode was studied by polarography using an open platinum electrode. As the electrode was brought from the depth of the liquid phase to its surface, an increase in the current under aerobic conditions was observed, due to diffusion of oxygen through the interface. The formation of lipid monolayers of phosphatidylcholine, stearic acid, hexadecanol, octadecanol, eicosanol, and docosanol on the water surface led to a decrease in diffusion current; the effect being most pronounced at a minimal depth of immersion of the electrode. The maximum value of the relative decrease in diffusion current R was obtained for docosanol monolaers. It was shown that the R value increases with increasing surface pressure in monolayers of phosphatidylcholine and stearic acid. It is assumed that the decrease in diffusion flow of O2 in the presence of monolayers is caused by the formation of an energy barrier that prevents the sorption of O2, which is related to the presence of hydrocarbon chains weakly interacting with oxygen.     

The active component in the flax-retting system of the zygomycete Rhizopus oryzae sb is a family 28 polygalacturonase

The zygomycete Rhizopus oryzae sb is a very efficient organism for retting of flax, the initial microbiological step in the process of making linen. An extracellular polygalacturonase, when isolated could perform retting, and therefore probably is the key component in the retting system of R. oryzae. This was purified and characterized. The purified enzyme has a molecular mass of 37,436 Da from mass spectrometric determination, an isoelectric point of 8.4, and has non-methylated polygalacturonic acid as its preferred substrate. Peptide sequences indicate that the enzyme belongs to family 28, in similarity with other polygalacturonases (EC. 3.2.1.15). It contains, however an N-terminal sequence absent in other fungal pectinases, but present in an enzyme from the phytopathogenic bacterium Ralstonia solanacearum. The biochemical background for the superior retting efficiency of R. oryzae sb is discussed.     

Retting pits for textile fibre plants at Danish prehistoric sites dated between 800 b.c. and a.d. 1050

During the last decade, a new type of structure has been found at several archaeological sites in Denmark. These structures can be interpreted as having been used for retting the stems of textile plants such as Linum usitatissimum L. (flax), Cannabis sativa L. (hemp) and Urtica dioica L. (nettle). In order to obtain fine threads for textile production, these plants need to pass through several biological and technical processes. The first process is the retting of the plant stems to dissolve the pectin which fixes the fibres to the stalk. This can either be done by water retting, where the plant stems are soaked in lakes, rivers or waterlogged pits, or by field retting, where the stems are laid out in a field in order to absorb dew. The first method is shorter in time and the process is easier to control. In this article, details of archaeological structures are presented from eight sites in southern Scandinavia that can be interpreted as textile plant retting pits. The constructions of the pits are described, as well as the archaeological contexts and the relevant associated archaeobotanical records. Some of the presented sites, of which the oldest are dated to the late Bronze Age and early pre-Roman Iron Age (800–250 b.c.) and the youngest to the Viking Age (a.d. 750–1050), indicate a large-scale production of flax that had been underestimated up to now.     

Establishment of the fungal entomopathogen Beauveria bassiana as a season long endophyte in jute (Corchorus olitorius) and its rapid detection using SCAR marker

An experiment was conducted to introduce the entomopathogen Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) as an endophyte in jute (Corchorus olitorius), a bast fibre crop through seed treatment. Colonization of root, leaf, stem, capsule, and seed were assessed through plating on selective medium and PCR based detection using B. bassiana specific SCAR markers. Endophytic colonization was detected in all the plants grown from treated seeds, but all the plant parts were not colonized. Colonization was detected in leaves, stems, and green capsules but not in roots and seeds. The endophytic colonization was influenced by both plant part and sampling period. Colonization was greater in leaves (55.87%) compared to stems (12.53%) and capsules (42.44%). The percent colonization was higher in case of 60?days old plants (43.34%) than in 30?days (23.89%) and 120?days (35.39%) old plants. As B. bassiana has already been reported to be pathogenic on jute pests, namely semilooper (Anomis sabulifera) and bihar hairy caterpillar (Spilosoma obliqua), its season long endophytic colonization within jute plant suggests a novel approach of biological control of these pests through seed treatment with the entomopathogen.     

On the role of cell wall lignin in determining the fineness of jute fibre

Though finer quality fibre is of great demand in the industry, a reasonable biological assessment of the factors controlling jute fibre fineness is lacking. Our aim was to relate lignin synthesis and accumulation in the secondary wall of the fibre cells with fibre fineness by anatomical and physiological evidences. Several jute genotypes including a low lignin mutant, dlpf (INGR No. 04107) and its lignin sufficient parent (JRC 212) were grown under different growth conditions. Their cell wall morphology and cellulose, hemicellulose and lignin content of fibre were estimated. The fineness of the extracted fibre was examined gravimetrically as well as by air-flow method on individual plant basis to relate it with their chemical constituents. Effect of incident light and some plant growth regulators on glucan and lignin biosynthetic enzymes as well as fibre fineness was determined. Positive relationship between cell wall thickness and lignin and negative relationship between fibre fineness and lignin of jute fibre were established. Application of the GA biosynthetic inhibitor helped to reduce lignin synthesis and to increase fibre fineness. Genotypes with thinner cell wall and lesser lignin may be utilized in breeding for improving the fibre fineness of jute. Field application of GA biosynthetic inhibitors, like daminozide, is recommended to reduce the cell wall thickness of lignin sufficient high yielding jute varieties.