Search

Polyaromatic hydrocarbons (PAHs) utilizing bacteria were isolated from soils of seven sites of Mathura refinery, India. Twenty-six bacterial strains with different morphotypes were isolated. These strains were acclimatized to utilize a mixture of four polycyclic aromatic hydrocarbons, i.e., anthracene, fluorene, phenanthrene, and pyrene, each at 50 mg/L concentration as sole carbon source. Out of total isolates, 15 potent isolates were subjected to 16S rDNA sequencing and identified as a member of diverse genera, i.e., Bacillus, Acinetobacter, Stenotrophomonas, Alcaligenes, Lysinibacillus, Brevibacterium, Serratia, and Streptomyces. Consortium of four promising isolates (Acinetobacter, Brevibacterium, Serratia, and Streptomyces) were also investigated for bioremediation of PAH mixture. This consortium was proved to be efficient PAH degrader resulting in 40-70 % degradation of PAH within 7 days. Results of this study indicated that these genera may play an active role in bioremediation of PAHs.

Overall economics of the biomass to ethanol process is largely determined by the efficiency of biomass hydrolysis. Performance of cellulase cocktails used for saccharification of cellulose in biomass is often limited by lower amounts of β-glucosidases present, which catalyse hydrolysis of cellobiose, the product of endo and exocellulases to glucose. Inappropriate ratio of these enzymes in commercial cocktails leads to accumulation of cellobiose which inhibits the activity of cellulases. Thus, this rate limiting enzyme is of crucial importance in determining the efficiency of commercial cellulases. The saprophytic fungus Trichoderma sp., exploited for production of commercial cellulases, produces very minute quantities of β-glucosidases as compared to endo and exocellulases. However, several other organisms are known to produce β-glucosidases in higher quantities, over a broader substrate range. Strategies to get optimal ratio of exocellulases, endocellulases and β-glucosidases to enhance saccharification yields are, therefore, discussed. Appropriate levels of β-glucosidase activity in commercial cocktails have been obtained by supplementing with accessory β-glucosidases, transgenic approaches and by optimizing β-glucosidase production through manipulation of culture conditions. These approaches have resulted in achieving higher β-glucosidase activity in cellulase cocktails, facilitating higher sugar yields and thereby potentially improving enzymatic saccharification of biomass and eventually ethanol production.

Bioprospecting activities tap vast sources of microbes from diverse and extreme habitats. Microbial hydrolases are important in the development of sustainable biomass energy or biofuels. To achieve full potential of this resource, there is a need to discover novel, unexploited microbes and their enzymes. So, a bioprospecting survey was conducted to identify fungal sources of biomass hydrolysing enzymes from different environments. Out of the total isolates, 39 were found to exhibit cellulolytic, hemicellulolytic and ligninolytic activities. Qualitative enzyme assays were performed using specific soluble substrates. Submerged fermentation of paddy straw/carrot grass (Parthenium hysterophorus) was then done to quantify the lignocellulolytic potential of all the isolates. The isolate CM20, identified to be Aspergillus terreus, was found to be a superior producer of cellulases and xylanases, while the isolate LG7, identified as Myrothecium roridum, was found to produce ligninolytic enzymes in high amounts. The study, therefore, resulted in the identification of cellulolytic and ligninolytic fungi which could be used in biorefineries for the development of greener energy.

A field experiment was conducted to evaluate the relative contribution of organic fertilizers (paddy straw, microbial inoculants and vermicompost) and inorganic fertilizers (urea and superphosphate) in improving pH, C, N, humus, microbial biomass, dehydrogenase, phosphatase, cellulase, beta-glucosidase and xylanase activities of soil under wheat crop. Vermicompost fertilization resulted in highest microbial biomass, available phosphorus, and nitrogen content of wheat soil. It was also found effective in minimizing the alkalinity of soil compared to other treatments as indicated by pH change. However incorporation of paddy straw in conjunction with N(60)P(60) and T. reesei inoculation resulted in maximum dehydrogenase, alkaline phosphatase and highest humus content of soil. Mixed inoculation of A. awamori and T. reesei did not prove effective in improving the soil biochemical properties in comparison to single inoculation of T. reesei. Results showed that in situ incorporation of paddy straw in combination with N(60)P(60) and T. reesei inoculation can be used as an effective measure for valuable disposal of paddy straw and to improve the soil health by reducing mineral fertilization.

The filamentous bacteria Streptomyces spp. produces diverse extracellular enzymes and other secondary metabolites. Proteomic analysis of the secretome of holocellulolytic Streptomyces sp. ssr-198 was done by tandem mass spectrometry using an Orbitrap Velos hybrid mass spectrometer. A wide range of hydrolytic enzymes, including glycoside hydrolases (17), proteases (17), polysaccharide lyases (3), esterases (2), and hypothetical proteins (14) were detected in the secretome analyzed. Overall, the secretome composition constituted of 12.50% cellulases, 17.50% hemicellulases, 21.25% proteases, 17.50% hypothetical proteins, and 31.25% other proteins. Comprehensive analysis of secretome will be useful in gaining better understanding of the unique role of hydrolytic enzymes in lignocellulose hydrolysis and helps in determining the industrial applications of these potent enzymes.

A total of 10 cellulase-producing bacteria were isolated from soil samples irrigated with paper and pulp mill effluents. The sequencing of 16S rRNA gene revealed that all isolates belonged to different species of genus Bacillus. Among the different isolates, B. subtilis IARI-SP-1 exhibited a high degree of β-1,4-endoglucanase (2.5 IU/ml), β-1,4-exoglucanase (0.8 IU/ml), and β-glucosidase (0.084 IU/ml) activity, followed by B. amyloliquefaciens IARI-SP-2. CMC was found to be the best carbon source for production of endo/exoglucanase and β-glucosidase. The β-1,4-endoglucanase gene was amplified from all isolates and their deduced amino acid sequences belonged to glycosyl hydrolase family 5. Among the domains of different isolates, the catalytic domains exhibited the highest homology of 93.7%, whereas the regions of signal, leader, linker, and carbohydrate-binding domain indicated low homology (73-74%). These variations in sequence homology are significant and could contribute to the structure and function of the enzyme.

After the publication of this work (1), we found that Table 4, which was adopted from our earlier study to substantiate the bacterial identification based on biochemical profiling with 16S rRNA gene sequencing, but due to oversight it could not be cited properly. Now we incorporated the corrected data with citation of source and modified as Table 4. Except some of the text in the methods; like for DNA isolation, gene amplification and sequencing, overlapping with our earlier publication (2), all the rest of the data is novel. We would like to thank Dr. Philippa Harris, Executive Editor for incorporating the correction.

For successful commercialization of biomass to ethanol process, the techno- economic hurdles have to be overcome. Complete substrate utilization is the key for making economics favorable. Existing enzyme preparations do not give high saccharification efficiency, thus, a broader suite of hydrolases is required. Xylanase supplementation in enzyme cocktail is an important strategy to increase sugar yields. In our study, hyperxylanolytic Aspergillus awamori F18 was used to produce xylanase. A. awamori F18 expressed high levels of xylanase during Solid state fermentation of corncob and also, Carboxy Methyl Cellulase (CMCase), filter paper activity (FP lyase) and β-glucosidase (524.43, 43.95, 8.64 and 29.81 IU mg-1 proteins respectively). A 10.6-12.5 fold concentration of these activities was achieved by single-step acetone precipitation. Supplementing concentrated xylanase to Accellerase®1500 resulted in 69.5% enhancement in sugars released after 72 h of saccharification of steam-pretreated rice straw. HPLC analysis of hydrolysates showed higher glucose levels along with the presence of xylose and arabinose. There was a 12.4% increase in the amounts of glucose as well as total sugars released when xylanase was supplemented to commercial cellulase and β-glucosidase.

1 Division of Agricultural Chemicals, Indian Agricultural Research Institute, New Delhi 110 012, India 2 Division of Environmental Sciences, Indian Agricultural Research Institute, New Delhi 110 012, India 3 Division of Microbiology, Indian Agricultural Research Institute, New Delhi 110 012, India 4 National Centre for Conservation and Utilization of Blue Green Algae, Indian Agricultural Research Institute, New Delhi 110 012, India 5 Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi 110 012, India

Proteases produced by Xenorhabdus are known to play a significant role in virulence leading to insect mortality. The present study was undertaken to purify and characterize protease from Xenorhabdus indica, an endosymbiont of nematode Steinernema thermophilum, and to decipher its role in insect mortality and its efficacy to control Helicoverpa armigera. A set of 10 strains of Xenorhabdus isolated from different regions of India were screened for protease activity on the basis of zone of clearing on gelatin agar plates. One potent strain of Xenorhabdus indica was selected for the production of protease, and the highest production (1,552 U/ml) was observed at 15-18 h of incubation at 28oC in soya casein digest broth. The extracellular protease was purified from culture supernatant using ammonium sulfate precipitation and ion-exchange chromatography. The enzyme was further characterized by SDS-PAGE and zymography, which confirmed the purity of the protein and its molecular mass was found to be ~52 kDa. Further MALDI-TOF/TOF analysis and effect of metal chelating agent 1,10-phenanthrolin study revealed the nature of the purified protease as a secreted alkaline metalloprotease. The bioefficacy of the purified protease was also tested against cotton bollworm (Helicoverpa armigera) and resulted in 67.9 ± 0.64% mortality within one week. This purified protease has the potential to be developed as a natural insecticidal agent against a broad range of agriculturally important insects.

Phytopathogenic fungi develop unique systems for fast invasion by producing hydrolases, which may be explored as a source of hydrolytic enzymes for biofuel research. The present work deals with evaluation of a potato pathogen Phoma exigua ITCC 2049 for its potential to produce cellulase and xylanase enzyme. Taguchi methodology was applied to reveal the influence and contribution of five important factors (carbon source, organic and inorganic nitrogen source, surfactant, and pH) on hydrolytic enzyme production by Phoma. Cultivation of fungus under optimized condition produced endoglucanase (37.00 IU/ml), FPase (1.13 IU/ml), β-glucosidase (2.67 IU/ml) and xylanase (24.92 IU/ml) within 8 days of submerged fermentation. Saccharification of biopretreated Parthenium and paddy straw with cocktail of Phoma secretome supplemented with commercial β-glucosidase resulted in the significantly higher reducing sugar yield (651.04–698.11 mg/gds). This study proves the potential of Phoma as an alternative source of enzymes for biomass saccharification.

A set of 300 bacterial strains isolated from various extreme environments were screened for the presence of cellulase activity on CMC agar plates. Phylogenetic analysis of the positive strain, based on 16S rRNA gene sequences indicated that the isolates were clustered within Firmicutes and Actinobacteria. A majority (17) of the isolates were identified as Bacillus, Paenibacillus, and Lysinibacillus sp., and the remaining three were identified as Arthobacter, Rhodococcus, and Bhargavaea cecembensis. Among the 20 positive isolates, 6 were evaluated for the production of cellulases on five different cellulosic substrates. Two isolates, B. cecembensis and Bacillus sp., based on maximum enzyme production on all cellulosic substrates, especially CMC and rice straw, were evaluated in terms of enzyme properties and kinetics. The enzymes of these two isolates are found to be active over broad range of pH and temperature. Such thermostable enzymes facilitate the development of efficient and cost-effective forms of the simultaneous saccharification and fermentation process converting lignocellulosic biomass into biofuels and value-added products.

The potential of Parthenium sp. as a feedstock for enzymatic saccharification was investigated by using chemical and biological pretreatment methods. Mainly chemical pretreatments (acid and alkali) were compared with biological pretreatment with lignolytic fungi Marasmiellus palmivorus PK-27. Structural and chemical changes as well as crystallinity of cellulose were examined through scanning electron microscopy, fourier transform infra red and X-ray diffraction analysis, respectively after pretreatment. Total reducing sugar released during enzymatic saccharification of pretreated substrates was also evaluated. Among the pretreatment methods, alkali (1 % NaOH) treated substrate showed high recovery of acid perceptible polymerised lignin (7.53 ± 0.5 mg/g) and significantly higher amount of reducing sugar (513.1 ± 41.0 mg/gds) compared to uninoculated Parthenium (163.4 ± 21.2) after 48 h of hydrolysis. This is the first report of lignolytic enzyme production from M. palmivorus, prevalent in oil palm plantations in Malaysia and its application in biological delignification of Parthenium sp. Alkali (1 % NaOH) treatment proves to be the suitable method of pretreatment for lignin recovery and enhanced yield of reducing sugar which may be used for bioethanol production from Parthenium sp.

The present communication is an attempt to explore the synergistic effect of two indigenous phosphate solubilizing bacteria (PSB) (Pseudomonasfluorescens BAM-4 and Burkholderia cepacia BAM-12) and arbuscular mycorrhizal (AM) fungus, Glomus etunicatum on growth, yield and nutrient uptake of wheat plants grown in nutrient deficient soils in pots amended with tricalcium phosphate (TCP). A significant increase in growth, yield and nutrient uptake of wheat plants was noticed and both strains of PSB interacted positively with AM fungus towards all growth parameters studied. A remarkable enhancement of seed yield was recorded notably by 92.8% and an increase in percent root colonization of AM and PSB population in soil was also recorded with time.

Polycyclic aromatic hydrocarbons (PAHs) are wide spread industrial pollutants that are released into the environment from burning of coal, distillation of wood, operation of gas works, oil refineries, vehicular emission, and combustion process. In this study a lipolytic bacterium was isolated from mixed stover compost of Saccharum munja and Brassica campestris. This strain was identified by both classical and 16S ribosomal DNA sequencing method and designated as Serratia marcesencs L-11. HPLC-based quantitation revealed 39- 100% degradation of PAH compounds within seven days. Further its ability to produce catechol 1, 2-dioxygenase (1.118 μM mL(-1) h(-1)) and biosurfactants (0.88 g L(-1)) during growth in PAH containing medium may be responsible for its PAH-degradation potential. This novel bacterium with an ability to produce lipases, biosurfactant and ring cleavage enzyme can prove to be useful for in-situ degradation of PAH compounds.

This study was conducted to assess the effect of microbial inoculation in Jatropha cake composting with different vegetable waste. The microbial inoculums composed of fungal strains (Aspergillus awamori, Aspergillus nidulans, Trichoderma viride, Phanerochaete chrysosporium) and bacterial inoculums (Pseudomonas striata as phosphorus solublizer and Azotobacter chroococcum as nitrogen fixer) were added to the compost mixture after the thermophilic phase was over for bioaugmenting of Jatropha cake under aerobic and partial anaerobic conditions. Addition of both fungal and bacterial inoculum with mixed substrate (Jatropha cake + vegetable waste) during composting (aerobic and partial anaerobic) showed, better results as compared to compost with only fungal inoculants. Increased enzymatic activity initially, during composting (like dehydrogenase, alkaline phosphatase activity and FDA) proved role of inoculated microbes in rapid decomposition. Analysis of compost (with both bacterial and fungal inoculum) showed presence of high humus (12.7%), humic acid (0.5%), fulvic acid (5.68%), soluble protein content and low C/N ratio. Decreased in concentration of extractable metals (Cu, Fe and Mn) were recorded at maturity in all the substrate composts. The C/N ratio was significantly correlated to parameters like humic acid, humus, fulvic acid, protein and also microbial activity parameters. We conclude that the composting of de-oiled Jatropha cake with different vegetables waste could be feasible and sustainable approach in recycling of agricultural and industrial residues in huge quantities.

Soil microorganisms are known to play an active role in increased crop yields and soil fertility through a diverse array of mechanisms and such organisms are termed as PGPR (Plant Growth Promoting Rhizobacteria). This enhancement has been attributed to their involvement in the cycle of nutrients like carbon and nitrogen or in the decomposition of the organic matter, or production of allelopathic metabolites or enzymes influencing the pathogenic flora/fauna which indirectly promotes plant growth. Cyanobacteria are a ubiquitous group of organisms which have been relatively less investigated as PGPR, although their role in nitrogen dynamics of paddy based cropping systems is well investigated. Cyanobacteria are known to produce compounds with a wide range of activities, including phytohormones, biocidal metabolites or nutraceuticals. The interactions between agriculturally useful heterotrophic bacteria and autotrophs such as cyanobacteria can be effective and environment friendly options as biocontrol agents and biofertilizers. Plant-microbe partnerships are increasingly being focussed for not only nutrient management, but also for improving biomass production and remediation of polluted/inhospitable environments. This compilation provides an overview of the developments on this aspect and projections for the future.

Agro residues, a precious source of nutrients are being disposed off because of their bulky nature and non-availability of management practices. Besides loss of essential plant nutrients and organic matter important for sustainability of the system, it also causes environmental pollution leading to animal and human health problems. It is important to recycle these crop residues for restoring soil health and sustainability of the production system for national food and nutritional security. Composting can be adopted for large scale recycling of these agrowastes to enriched compost using efficient microorganisms. Apart from being a source of nitrogen, phosphorus, potassium, and other nutrients for plants, compost is also believed to suppress soil-borne diseases in plants. These virtues make composting an ideal option for processing the enormous quantities of agro wastes that are generated in the world. Besides this agrowastes may be utilized as a resource for production of animal feed, biofuel and enzyme to generate additional income.

Pseudomonads have been reported for their metabolic, nutritional and ecological versatility, which motivated us to prospect the metabolic profile of a lipolytic strain Pseudomonas aeruginosa SL-72. The strain SL-72 was found to produce high levels of lipase and pectinase (1,555.62 IU/mL and 1,490.33 IU/mL, respectively), esterase and amylase, besides low levels of xylanase, proteinase and cellulase. The strain also tested positive for different plant growth-promoting traits—production of ammonia, hydrogen cyanide, siderophores, phosphate solubilization, nitrate reduction and antifungal activity. The high levels of activity of aryl sulphatase, alkaline phosphatase and fluorescein diacetate hydrolase makes it a useful strain for enhanced nutrient cycling in soil. The strain SL-72 produced rhamnolipids, a biosurfactant and its production was enhanced when starch was used as carbon source (0.256 g/L) and utilized polycyclic hydrocarbon compounds viz. anthracene, phenanthrene, pyrene, fluorene and its mixture. The multifaceted nature of the culture illustrates its promise in bioremediation, industry, besides its use as an inoculant.

Delignification of paddy straw with the white-rot fungus, Trametes hirsuta under solid state fermentation, for enhanced sugar recovery by enzymatic saccharification was studied. T. hirsuta MTCC136 showed high ligninase and low cellulase activities. Solid state fermentation of paddy straw with T. hirsuta enhanced carbohydrate content by 11.1% within 10 days of incubation. Alkali extracts of Trametes pretreated paddy straw showed high absorbance at 205 nm indicating high lignin break down. The amount of value-added lignin recovered from the Trametes pretreated paddy straw was much higher than controls. Enzymatic hydrolysis of the Trametes pretreated paddy straw yielded much higher sugars than controls and yields increased till 120 h of incubation. Saccharification efficiency of the biologically pretreated paddy straw with Accelerase®1500 was 52.69% within 72 h and was higher than controls. Thus, the study brings out the delignification potential of T. hirsuta for pretreatment of lignocellulosic substrate and facilitating efficient enzymatic digestibility of cellulose.

The performance of three selected bacterial strains-PR3, PR7 and PR10 (Providencia sp., Brevundimonas sp., Ochrobacterium sp.) and three cyanobacterial strains CR1, CR2 and CR3 (Anabaena sp., Calothrix sp., Anabaena sp.), and their combinations was evaluated in a pot experiment with rice variety Pusa-1460, comprising 51 treatments along with recommended fertilizer controls. Highest yield enhancement of 19.02% was recorded in T12 (CR2), over control, while significant enhancement in nitrogen fixing potential was recorded in treatments involving combination of bacterial-cyanobacterial strains-T37 (PR3 + CR1 + CR3) and T21 (PR7 + CR1). Organic carbon was significantly increased in all microbe-inoculated treatments, which could be correlated with microbial biomass carbon values and activities of all the enzymes tested in our study. Also, panicle weight and plant biomass were highly correlated with soil microbial carbon. Comparative evaluation revealed the superior performance of strains CR2, CR1 (both Anabaena sp.) and PR10 (Ochrobacterium sp.) in increasing the growth and grain yield of rice and improving soil health, besides N (nitrogen) savings of 40-80 kg ha(-1). The study for the first time illustrated the positive effects of co-inoculation of bacterial and cyanobacterial strains for integrated nutrient management of rice crop.

The present work describes electrophoretic fabrication of nanostructured chitosan-zirconium-oxide composite (CHIT-NanoZrO(2)) film (180 nm) onto indium-tin-oxide (ITO)-coated glass plate. This nanobiocomposite film has been explored as immobilization platform for probe DNA specific to M. Tuberculosis as model biomolecule to investigate its sensing characteristics. It is revealed that pH-responsive behavior of CHIT and its cationic skeleton is responsible for the movement of CHIT-NanoZrO(2) colloids toward cathode during electrophoretic deposition. The FT-IR, SEM, TEM, and EDX techniques have been employed for the structural, morphological, and composition analysis of the fabricated electrodes. The morphological studies clearly reveal uniform inter-linking and dispersion of hexagonal nanograins of ZrO(2) (30-50 nm) into the chitosan matrix, resulting in homogeneous nanobiocomposite formation. Electrochemical response measurements of DNA/CHIT-NanoZrO(2)/ITO bioelectrode, carried out using cyclic voltammetry and differential pulse voltammetry, reveal that this bioelectrode can specifically detect complementary target DNA up to 0.00078 μM with sensitivity of 6.38 × 10(-6) AμM(-1).

Rice fields represent “hot spots of biodiversity” – encompassing a complicated network of aerobic, anaerobic and facultative micro-organisms, whose interactions with the resident macro flora and fauna lead to unique and complex biochemical and physicochemical reactions. In turn, these reactions fuel the major nutrient cycles. The dynamics of microbiological activity of rice soil, especially in the rhizosphere, represents a model system to study the fundamentals of microbial ecology, such as the mechanisms for maintenance and communication between diverse and overlapping bacterial populations. Modern molecular tools such as innovative micro-scale-measuring devices and use of extensive long-term field data have revealed the culturable/unculturable diversity – which includes not only the commonly recorded eubacteria and cyanobacteria but also members of Archaea, Planctomycetes, β-Proteobacteria, and an increasing number of associated endophytes. This compilation presents the current knowledge about this key soil habitat and its global significance to agriculture and the environment.

Poultry manure and fungal consortium developed by including fungi of genus Aspergillus , Trichoderma and Phanerochaete were evaluated separately to degrade high silica paddy straw. The quality evaluation of composted organic wastes after two months of decomposition revealed that poultry manure amended paddy straw compost had a C:N ratio of 13.06 and germination index of 132%, compared to 15.29 and 114% of its fungal inoculated counterpart. Supplementation of paddy straw with poultry manure was as effective as its bioaugmentation with fungal consortium. The incorporation of poultry manure @ 3 t ha −1 (T3) and poultry manure amended paddy straw compost @ 3 t ha −1 + N 60 P 40 K 30 (T4) separately to soil under rice crop for two consecutive years, resulted in improved microbial biomass and different enzymatic activities responsible for nutrient cycling. T3 and T4 treatments recorded a grain yield improvement of 54.87 and 79.26% respectively in 2007 and 79 and 80.2% respectively in 2008 compared to N 120 P 80 K 60 .

Markers for evaluating the establishment of cyanobacteria based on their sensitivity or resistance to antibiotics, saccharide utilization patterns and PCR generated fingerprints were developed. Four selected strains (isolates from rhizosphere soils of diverse agro-ecosystems) have shown potential as diazotrophs and exhibited plant growth promoting abilities. Different responses were obtained on screening against 40 antibiotics, which aided in developing selectable antibiotic markers for each strain. Biochemical profiles generated using standardized chromogenic identification system (including saccharide utilization tests) revealed that 53 % of the saccharides tested were not utilized by any strain, while some strains exhibited unique ability for utilization of saccharides such as melibiose, cellobiose, maltose and glucosamine. PCR based amplification profiles developed using a number of primers based on repeat sequences revealed the utility of 3 primers in providing unique fingerprints for the strains.

Bacillus subtilis strain RP24, isolated from rhizoplane of field grown pigeon pea, exhibited in vitro antagonism against a wide range of phytopathogenic fungi. An attempt was made to partially purify and characterize the diffusible antifungal metabolite/s produced by the strain RP24 and its negative mutant (NM) in potato dextrose medium. High performance liquid chromatography (HPLC) of partially purified extract of RP24 showed the presence of lipopeptide antibiotic iturin as a major peak that was comparable to that of standard iturin A (5.230 min) from Sigma–Aldrich whereas the corresponding peak was absent in extract of NM. The structure was further confirmed by liquid chromatographic mass spectrometric (LCMS) analysis as iturin A. LCMS analysis also showed the presence of surfactin and fengycin besides iturin A. Amplification of the lpa-14 (encodes the 4′-phosphopantetheinyl transferase required for the maturation of template enzyme of iturin A) and ituD (encodes a putative malonyl coenzyme A transacylase, whose disruption results in a specific deficiency in iturin A production) genes of iturin operon of strain RP24 was carried out and the sequences obtained were compared with the existing database of NCBI. The sequences of lpa-14 and ituD gene of RP24 showed 98% and 97% homology with lpa-14 and ituD genes of B. subtilis in the existing database. The results indicated that strain RP24 harbors iturin operon in its genome and a chemical mutation in this operon might have resulted in loss of antifungal activity in the negative mutant.

Poultry droppings, neem cake, castor cake, jatropha cake and grass clippings were used separately as organic nitrogen additives to decrease the high C:N ratio of wheat straw. Composting was carried out aerobically in presence of fungal consortium developed by including Aspergillus awamori, Aspergillus nidulans, Trichoderma viride and Phanerochaete chrysosporium. The degraded product was characterized to assess the technical viability of organic nitrogen supplements as well as fungal consortium in improving the quality of compost and hastening the process of decomposition of high lignocellulolytic waste. Evaluation of maturity showed that mixture of wheat straw, poultry dropping and jatropha cake had the lowest C:N ratio of 10:1, the highest humic acid fraction of 3.15%, the lowest dehydrogenase activity and a germination index exceeding 80% in 60 days of decomposition. Inoculated and grass clipping amended wheat straw-poultry dropping mixture resulted in compost with highest humus content of 11.8% and C:N ratio of 13.5, humic acid fraction of 2.84% and germination index of 59.66%. Fungal consortium was effective in improving the humus content of all the composted mixtures. In some treatments, germination index could not be correlated with C:N ratio. Non edible oil seed cake supplemented substrate mixtures did not respond to fungal inoculation as far as C:N ratio was concerned.

The influence of plant growth promoting bacteria (PGPB) and cyanobacteria, alone and in combination, was investigated on micronutrient enrichment and yield in rice–wheat sequence, over a period of two years. Analysis of variance (ANOVA) in both crops indicated significant differences in soil dehydrogenase activity and micronutrient enrichment in grains (Fe, Zn in rice, and Cu, Mn in wheat). The combined inoculation of Anabaena oscillarioides CR3, Brevundimonas diminuta PR7, and Ochrobactrum anthropi PR10 (T6) significantly increased nitrogen, phosphorus, and potassium (NPK) content and improved rice yield by 21.2%, as compared to the application of recommended dose of NPK fertilizers (T2). The treatment T5 (Providencia sp. PR3 + B. diminuta PR7 + O. anthropi PR10) recorded an enhancement of 13–16% in Fe, Zn, Cu, and Mn concentrations, respectively, in rice grains. In wheat, Providencia sp. PW5 (T6) recorded the highest yield (5.23 Mg ha−1) and significantly higher enrichment of Fe and Cu (44–45%) in the grains. This study highlighted the promise of combinations of cyanobacteria/bacteria and their synergistic action in biofortification and providing savings of 40–60 kg N ha−1. Future focus needs to be towards integrating such promising environment-friendly and environmentally sustainable options in nutrient management strategies for this cropping sequence.

A glasshouse experiment was conducted to investigate the influence of arbuscular mycorrhizal fungi (AMF) and mycorrhiza helper bacteria (MHB) on growth, osmotic adjustment, and antioxidant activities in Troyer citrange and Cleopatra mandarin in pot culture under well-watered (WW) and water stress (WS) conditions. After 270 days of inoculation with microbial culture(s), half of the seedlings of each genotype were subjected to water stress and the other half were WW for 20 days. During the moisture stress mycorrhizal root colonization showed a durative reduction. No mycorrhizal colonization was observed in the roots of non-AM seedlings. Troyer citrange and Cleopatra mandarin recorded significantly highest root colonization just before imposing differential water treatment (83.34 and 80.00%, respectively) and after 20 days of differential water treatment (66.67 and 62.50%, respectively) under WS and (87.50 and 83.33%, respectively) under WW, when dually inoculated with Glomus intraradices and PSB. Glomus intraradices in association with PSB or Azospirillum accumulated higher concentration of osmolytes like total phenols, proline and total soluble sugars and antioxidant metabolites (carotenoids and ascorbic acid) in leaves of citrus seedlings under WS.

Out of 10 thermophilic fungi isolated from wheat straw, farm yard manure, and soil, only three showed highest cellobiase, carboxymethyl cellulase, xylanase, and FPase activities. They were identified as Aspergillus nidulans (Th(4)), Scytalidium thermophilum (Th(5)), and Humicola sp. (Th(10)). A fungal consortium of these three fungi was used to compost a mixture (1:1) of silica rich paddy straw and lignin rich soybean trash. The composting of paddy straw for 3 months, during summer period in North India, resulted in a product with C:N ratio 9.5:1, available phosphorus 0.042% and fungal biomass 6.512 mg of N-acetyl glucosamine/100 mg of compost. However, a C:N ratio of 10.2:1 and highest humus content of 3.3% was achieved with 1:1 mixture of paddy straw and soybean trash. The fungal consortium was effective in converting high silica paddy straw into nutritionally rich compost thereby leading to economical and environment friendly disposal of this crop residue.

An investigation was directed towards biochemical characterization of cyanobacterium Calothrix elenkinii and analysis of the chemical nature and mode of action of its fungicidal metabolite(s) against oomycete Pythium debaryanum. Biochemical characterization of the culture in terms of carbohydrate utilization revealed the facultative nature of C. elenkinii. Unique antibiotic markers were also found for this strain. 16S rDNA sequencing of the strain revealed 98% similarity with Calothrix sp. PCC7101. The fungicidal activity was tested by disc diffusion assay of different fractions of the culture filtrate. A minimum inhibitory concentration of 10 microl was recorded for ethyl acetate fraction of the 7-weeks old culture filtrates. HPLC, followed by NMR spectral analysis demonstrated the presence of a substituted benzoic acid in the ethyl acetate fraction. Microscopic examination revealed distinct granulation, followed by disintegration of the hyphae of Pythium sp., indicating the presence of an active metabolite in the culture filtrates of Calothrix sp. The fungicidal activity of C. elenkinii can be attributed to the presence of 3-acetyl-2-hydroxy-6-methoxy-4-methyl benzoic acid. This is the first report of a benzoic acid derivative having fungicidal activity in cyanobacteria.

Background The objective of this study was to develop a consortium of effective microorganisms to hasten the composting process and to reduce the composting period. Results An efficient microorganism (EM) consortium was developed using Candida tropicalis (Y6), Phanerochaete chrysosporium (VV18), Streptomyces globisporous (C3), Lactobacillus sp. and enriched photosynthetic bacterial inoculum for rapid composting of paddy straw. Paddy straw was amended with poultry droppings to narrow down its C:N ratio for faster degradation. Composting was carried out in open pits with EM consortium and compared with compost inoculant (CI) consisting of Aspergillus nidulans (ITCC 2011), Trichoderma viride (ITCC 2211), Phanerochaete chrysosporium (NCIM 1073) and A. awamori (F-18). Changes in biochemical and physiochemical parameters like C:N ratio, pH, EC and humus were studied over a period of 60 days to test compost maturity and stability along with microbial and extracellular hydrolytic enzyme activities. Paddy straw amended with EM and CI hasten the composting process by bringing C:N ratio down to 15:1 and achieving a total humus content of 4.82 % within 60 days. High activity of hydrolytic enzyme carboxymethyl cellulase (CMCase) (0.43 IU/g) and microbial activity in terms of dehydrogenase (158.64 lg TPF/g/day) was observed in this treatment. The activity of xylanase was positively correlated (r = 0.987) with alkali-soluble carbon. Conclusion This study illustrates the importance of microbial bioaugmentation to hasten the composting process of paddy straw to produce quality compost.

Microorganisms play an important role in the recycling of agricultural wastes. The compost generated by bioconversion ofagroresidues offers several benefits such as enhanced soil fertility and soil health which can lead to increased agriculturalproductivity, improved soil biodiversity, reduced ecological risks and a healthier environment. These virtues makecomposting an ideal option for processing of the enormous quantities of agrowastes that are generated in the world.Recent reports also indicate multifarious uses of bioaugmented compost as carrier for bioinoculants, biocontrol agents fordiseases suppressivness and bioremediation. There is definite need to intensify research on novel effective microorganismsto prepare high quality compost in a relatively shorter duration and new technologies for large-scale production.Key Words: Compost; Agroresidues; Effective Microorganisms; Soil Health*Author for Correspondence: E-mails: latarajat@yahoo.co.in

Background Composting is microbial decomposition of biodegradable materials and it is governed by physicochemical, physiological and microbiological factors. The importance of microbial communities (bacteria, actinomycetes and fungi) during composting is well established. However, the microbial diversity during composting may vary with the variety of composting materials and nutrient supplements. Therefore, it is necessary to study the diversity of microorganisms during composting of different agricultural byproducts like wheat bran, rice bran, rice husk, along with grass clippings and bulking agents. Here it has been attempted to assess the diversity of culturable bacteria during composting of agricultural byproducts. Results The culturable bacterial diversity was assessed during the process by isolating the most prominent bacteria. Bacterial population was found to be maximum during the mesophilic phase, but decreased during the thermophilic phase and declined further in the cooling and maturation phase of composting. The bacterial population ranged from 105 to 109 cfu g-1 compost. The predominant bacteria were characterized biochemically, followed by 16S rRNA gene sequencing. The isolated strains, both Gram-positive and Gram-negative groups belonged to the order Burkholderiales, Enterobacteriales, Actinobacteriales and Bacillales, which includes genera e.g. Staphylococcus, Serratia, Klebsiella, Enterobacter, Terribacillus, Lysinibacillus Kocuria, Microbacterium, Acidovorax and Comamonas. Genera like Kocuria, Microbacterium, Acidovorax, Comamonas and some new species of Bacillus were also identified for the first time from the compost made from agricultural byproducts. Conclusion The use of appropriate nitrogen amendments and bulking agents in composting resulted in good quality compost. The culture based strategy enabled us to isolate some novel bacterial isolates like Kocuria, Microbacterium, Acidovorax and Comamonas first time from agro-byproducts compost. These bacteria can be used as potential compost inoculants for accelerating composting process.

The unstable and uncertain availability of petroleum sources as well as rising cost of fuels have shifted global efforts to utilize renewable resources for the production of greener energy and a replacement which can also meet the high energy demand of the world. Bioenergy routes suggest that atmospheric carbon can be cycled through biofuels in carefully designed systems for sustainability. Significant potential exists for bioconversion of biomass, the most abundant and also the most renewable biomaterial on our planet. However, the requirements of enzyme complexes which act synergistically to unlock and saccharify polysaccharides from the lignocellulose complex to fermentable sugars incur major costs in the overall process and present a great challenge. Currently available cellulase preparations are subject to tight induction and regulation systems and also suffer inhibition from various end products. Therefore, more potent and efficient enzyme preparations need to be developed for the enzymatic saccharification process to be more economical. Approaches like enzyme engineering, reconstitution of enzyme mixtures and bioprospecting for superior enzymes are gaining importance. The current scenario, however, also warrants the need for research and development of integrated biomass production and conversion systems.