A study of the structure-activity relationships of 5'-O-[N-(salicyl)sulfamoyl]adenosine (6), a potent inhibitor of the bifunctional enzyme salicyl-AMP ligase (MbtA, encoded by the gene Rv2384) in Mycobacterium tuberculosis, is described, targeting the salicyl moiety. A systematic series of analogues was prepared exploring the importance of substitution at the C-2 position revealing that a hydroxy group is required for optimal activity. Examination of a series of substituted salicyl derivatives indicated that substitution at C-4 was tolerated. Consequently, a series of analogues at this position provided 4-fluoro derivative, which displayed an impressive MIC99 of 0.098 microM against whole-cell M. tuberculosis under iron-limiting conditions. Examination of other heterocyclic, cycloalkyl, alkyl, and aminoacyl replacements of the salicyl moiety demonstrated that these nonconservative modifications were poorly tolerated, a result consistent with the fairly strict substrate specificities of related non-ribosomal peptide synthetase adenylation enzymes.

In order to improve the digestibility and nutrient availability in rumen, wheat straw was subjected to solid state fermentation (SSF) with white-rot fungi (i.e. Pleurotus ostreatus and Trametes versicolor) and the fermented biomass (called myco-straw) was evaluated for biochemical, enzymatic and nutritional parameters. The fungal treatment after 30 days led to significant decrease (P < 0.05) in cell wall constituents viz, acid detergent fiber (ADF), neutral detergent fiber (NDF), hemicellulose, lignin and cellulose to the extent of 35.00, 38.88, 45.00, 37.48 and 37.86%, respectively in P. ostreatus fermented straw, while 30.04, 33.85, 39.90, 31.29 and 34.00%, respectively in T. versicolor fermented straw. However, maximum efficiency of fermentation in terms of low carbohydrate consumption per unit of lignin degradation, favoring cattle feed production was observed for P. ostreatus on the 10th day (17.12%) as compared with T. versicolor on the 30th day (16.91%). The myco-straw was found to contain significantly high (P < 0.05) crude protein (CP; 4.77% T. versicolor, 5.08% P. ostreatus) as compared to control straw (3.37%). Metabolizable energy (ME, MJ/kg DM), percent organic matter digestibility (OMD) and short chain fatty acids (SCFAs; mmol) production also increased considerably from control straw (4.40, 29.91 and 0.292) to a maximum up to P. ostreatus fermented straw (4.92, 33.39 and 0.376 on 20th day) and T. versicolor fermented straw (4.66, 31.74 and 0.334 on 10th day), respectively. Moreover, the myco-straw had lower organic carbon and was rich in nitrogen with lower C/N ratio as compared to control wheat straw. Results suggest that the fungal fermentation of wheat straw effectively improved CP content, OM digestibility, SCFAs production, ME value and simultaneously lowered the C/N ratio, thus showing potential for bioconversion of lignin rich wheat straw into high energy cattle feed.

The synthesis, biochemical, and biological evaluation of a systematic series of 2-triazole derivatives of 5'-O-[N-(salicyl)sulfamoyl]adenosine (Sal-AMS) are described as inhibitors of aryl acid adenylating enzymes (AAAE) involved in siderophore biosynthesis by Mycobacterium tuberculosis. Structure activity relationships revealed a remarkable ability to tolerate a wide range of substituents at the 4-position of the triazole moiety and a majority of the compounds possessed subnanomolar apparent inhibition constants. However, the in vitro potency did not always translate into whole cell biological activity against M. tuberculosis, suggesting intrinsic resistance, due to limited permeability, plays an important role in the observed activities. Additionally, the well-known valence tautomerism between 2-azidopurines and their fused tetrazole counterparts led to an unexpected facile acylation of the purine N-6 amino group.

A native isolate of Pleurotus ostreatus HP-1 (Genbank Accession No. EU420068) was found to have an excellent laccase producing ability. The extracellular laccase was purified to electrophoretic homogeneity from copper sulphate induced solid-state fermentation medium by ammonium sulphate precipitation and ion-exchange chromatography. The enzyme was determined to be monomeric protein with an apparent molecular mass of 68,420 kDa, and an isoelectric point (pI) of 3.5. The inductively coupled plasma spectroscopy showed a presence of iron, zinc and copper in the purified enzyme. The absorption spectrum in the range of 200–700 nm showed the maximum absorption at 610 nm characteristic of fungal laccase and corresponding to the presence of type I copper atom. The laccase was stable at different temperatures up to 70 °C and retained 61 % activity at 50 °C. The enzyme reaction was inhibited by cysteine; sodium azide and EDTA. The enzyme oxidized various known laccase substrates, its lowest Km value being for ortho-dianisidine and highest Kcat and Kcat/Km for ABTS. The purified laccase exhibited different pH optima for different substrates. The N-terminal sequence did not show any similarity with N-terminal sequence of other species of genera Pleurotus.

India is amongst the largest banana (Musa acuminata) producing countries and thus banana pseudo stem is commonly available agricultural waste to be used as lignocellulosic substrate. Present study focuses on exploitation of banana pseudo stem as a source for bioethanol production from the sugars released due to different chemical and biological pretreatments. Two fungal strains Aspergillus ellipticus and Aspergillus fumigatus reported to be producing cellulolytic enzymes on sugarcane bagasse were used under co-culture fermentation on banana pseudo stem to degrade holocellulose and facilitate maximum release of reducing sugars. The hydrolysate obtained after alkali and microbial treatments was fermented by Saccharomyces cerevisiae NCIM 3570 to produce ethanol. Fermentation of cellulosic hydrolysate (4.1 g%) gave maximum ethanol (17.1 g/L) with yield (84%) and productivity (0.024 g%/h) after 72 h. Some critical aspects of fungal pretreatment for saccharification of cellulosic substrate using A. ellipticus and A. fumigatus for ethanol production by S. cerevisiae NCIM 3570 have been explored in this study. It was observed that pretreated banana pseudo stem can be economically utilized as a cheaper substrate for ethanol production.

Background:In current times, enzyme-catalyzed reactions have gained importance for the development of new chemical processes. These require the production of large quantity of enzyme at low cost. Solid-state fermentation (SSF) is an efficient process because this bioprocess has a potential to convert agro-industrial residues into valuable compounds. Hence, the current study focuses on the optimization of process parameters for the higher production of laccase using a novel basidiomycete fungi Tricholoma giganteum AGHP under solid-state fermentation (SSF). Further, the purification of laccase using column chromatographic technique was performed.Results: Various physico-chemical parameters were evaluated and maximum production obtained was 2.69 × 10 5 U/g using wheat straw as a dry substrate. Optimum pH was found to be 5.0 and the temperature of 30 °C with 0.3 mM copper as an inducer. The enzyme was purified from the initial protein preparation by two-step column chromatography. A yield of 10.49 % with 3.33-fold purification was obtained using Sephadex G-75 gel permeation chromatography. Further increase in purification (total) was found to be 10.80-fold with a yield of 8.50 % using DEAE Sephadex A-50 ion exchange column chromatography. The purified enzyme was identified as a monomeric protein with a molecular weight of 66 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Conclusion:In view of the results obtained, we can conclude that the extracellular laccase production is governed by various cultural parameters such as pH, temperature, and the composition of culture medium. "One-factor-ata-time" methodology was capable of establishing the optimum conditions that significantly increases the enzyme production several folds using lignocellulosic substrate. Therefore, laccase from T. giganteum AGHP has a potential in several industrial applications.

Lignocelluloses from agricultural, industrial, and forest residues constitute a majority of the total biomass present in the world. Environmental concerns of disposal, costly pretreatment options prior to disposal, and increased need to save valuable resources have led to the development of value-added alternate technologies such as bioethanol production from lignocellulosic wastes. In the present study, biologically pretreated (with the fungus, Pleurotus ostreatus HP-1) and chemically pretreated (with mild acid or dilute alkali) wheat straw (WS) and banana stem (BS) were subsequently subjected to enzymatic saccharification (with mixture of 6.0 U/g of filter paper cellulase and 17 U/g of β-glucosidase) and were evaluated for bioethanol production using Saccharomyces cerevisiae NCIM 3570. Biological and chemical pretreatments removed up to 4.0–49.2 % lignin from the WS and BS which was comparatively higher than that for cellulose (0.3–12.4 %) and for hemicellulose (0.7–21.8 %) removal with an average 5.6–49.5 % dry matter loss. Enzymatic hydrolysis yielded 64–306.6 mg/g (1.5–15 g/L) reducing sugars from which 0.15–0.54 g/g ethanol was produced from Saccharomyces cerevisiae NCIM 3570.

Hydrocarbon pollution is a perennial problem not only in India but throughout the globe. A plethora of microorganisms have been reported to be efficient degraders of these recalcitrant pollutants. One of the major concerns of environmental problem is the presence of hydrocarbons due to the various anthropogenic activities. PAHs are ubiquitous in naturei.e.present in soil, water and air. Presence of PAHs in environment creates problem as their presence have deleterious effect on human and animals. They also have the ability to cause the tumors in human and animals. Some of the microorganisms are capable of transforming and degrading these PAHs and remove them from the environment. The present review describes about the sources, structure, fate and toxicity of PAHs as well as different bioremediation techniques involved in the removing of contaminants from the environment which are efficient and cost-effective. The conventional approaches used for removal of PAH are not only environment friendly but also are able to reduce the risk to human and ecosystem.