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Plant cell walls are comprised of cellulose, hemicellulose and other polymers that are intertwined. This complex structure acts as a barrier to degradation by single enzyme. Thus, a cocktail consisting of bi and multifunctional xylanases and xylan debranching enzymes is most desired combination for the efficient utilization of these complex materials. Xylanases have prospective applications in the food, animal feed, and paper and pulp industries. Furthermore, in order to enhance feed nutrient digestibility and to improve wheat flour quality xylanase along with other glycohydrolases are often used. For these applications, a bifunctional enzyme is undoubtedly much more valuable as compared to monofunctional enzyme. The natural diversity of enzymes provides some candidates with evolved bifunctional activity. Nevertheless most resulted from the in vitro fusion of individual enzymes. Here we present bifunctional xylanases, their evolution, occurrence, molecular biology and potential uses in biotechnology.

The microenvironment of bacteria associated with the gastrointestinal tract of an animal in£uences the host in many ways, including the metabolism of several nutrients. Isolation, molecular characterization and enzymatic activities of culturable bacteria associated with the gastrointestinal tract of hatcheryreared oceanic yellow seahorse, Hippocampus kuda, were investigated in the present study. 16S rRNA sequencing of bacterial isolates yielded 10 di¡erent bacterial genera belonging to two major groups: proteobacteria (62.9%) and ¢rmicutes (37.03%). The predominant microbial £ora belonged to the genera Vibrio spp., Enterovibrio sp. and Bacillus spp. Burkholderia cenocepacia, hitherto unreported from the gastrointestinal tract of marine ¢sh, was retrieved from the seahorse gut, albeit in small numbers. Enzymatic studies indicated that the bacterial isolates possess the ability to degrade lipids, cellulose, xylan, starch and proteins. Lipase activity was exhibited by a majority of the isolates (70.4%), indicating that the bacterial £ora associated with the intestinal tract of seahorses is capable of digesting foods rich in lipids. The possible implications for the role of these bacteria in the digestion and physiological processes are discussed. To our knowledge, this is the ¢rst time that the characterization and enzymatic activities of bacteria associated with the intestinal tract of farmed seahorses have been reported.

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Monsoonal upwelling along south and central west coast of India leads to intense biological productivity. As a consequence of excess organic matter production following upwelling during June-October and low dissolved oxygen in the upwelled waters, denitrification occurs in the near shore waters. Implicitly, these processes ought to bring alterations in microbial communities. Therefore, diversity and community structure of bacteria from subsurface layers of a tropical region experiencing intense seasonal lows of oxygen were analyzed through sequencing of 16S rRNA gene clones. The overall diversity was more during hypoxic period of Fall intermonsoon (FIM, October) compared either to Spring intermonsoon (SIM, March) or summer monsoon (SuM, June) months. As many as 14 lineages of bacterial domains: Gammaproteobacteria (37%), Alphaproteobacteria (21%), Cyanobacteria (20%), Deltaproteobacteria (3%), Firmicutes (3%), Betaproteobacteria (2%), Acidobacteria (2%), Actinobacteria (7%), Marinimicrobia (2%), Bacteroidetes (1%), Verrucomicrobia (1%), Planctomycetes (0.4%), Chloroflexi (0.2%) and Omnitrophica bacterium (0.2%), were recognized from our coastal location. Notably, sequences of Planctomycetes, Chloroflexi and Omnitrophica bacterium were found exclusively during FIM. A generally higher representation of sequences of Betaproteobacteria during SuM and of Actinobacteria and Firmicutes during SIM was discernible. This study is thus useful to recognize that microbial community might undergo strong temporal shifts in the monsoon affected tropical coastal ecosystems. Keywords Tropical coastal ecosystem Á Goa Á Upwelling Á Hypoxia Á Bacterial community Á 16S rDNA clones Á Phylogenetic composition Electronic supplementary material The online version of this article (

Enzymatic hydrolysis of seaweed biomass was studied using xylanase produced from marine bacteria sp. strain BT21 through solid-state fermentation of wheat bran. Three types of seaweeds,, and, were selected as representatives of red, brown, and green seaweeds, respectively. Seaweed biomass was pretreated with hot water. The efficiency of pretreated biomass to release reducing sugar by the action of xylanase as well as the type of monosaccharide released during enzyme saccharification of seaweed biomass was studied. It was seen that pretreated biomass of seaweed , and, at 121 °C for 45 min, followed by incubation with 50 IU xylanase released reducing sugars of 233 ± 5.3, 100 ± 6.1 and 73.3 ± 4.1 µg/mg of seaweed biomass, respectively. Gas chromatography analysis illustrated the release of xylose, glucose, and mannose during the treatment process. Hot water pre-treatment process enhanced enzymatic conversion of biomass into sugars. This study revealed the important role of xylanase in saccharification of seaweed, a promising feedstock for third-generation bioethanol production.

Fish silage is a brown liquefied product achieved by the action of enzymes when finely grounded whole/parts of either single or mixed fish types are subjected to acidification. This study made a comparative assessment of biochemical and nutritive properties, especially the amino acid composition in supernatant phase of formic acid silages prepared from two fish types, Indian mackerel (Rastrelliger kanagurta) and false travely (Lactarius lactarius) representing fat fish (FF, fat content > 5%) and lean fish (LF, fat content < 5%), respectively during 35 days of fermentation (DoF). Significantly higher content of total amino acid (TAA) and free amino acids (FAA) were recorded in FFS (TAA, 41.2 ± 0.03 mg/g; FAA, 31.3 ± 0.003 mg/g) compared to LFS (TAA, 35.8 ± 0.07 mg/g; FAA, 18.26 ± 0.003 mg/g; FAA, 31.3 ± 0.003 mg/g) (p < 0.05). At the end of 35 DoF, the concentrations of amino acids such as asparagine, histidine, isoleucine, valine, cysteine, serine, lysine and arginine were significantly higher in FFS as compared to LFS. The relative amino acid composition of FFS and LFS varied in accordance with DoF and the relationship was found to be highly significant (ANOVA, p < 0.00001). High concentrations of l-amino acids such as leucine, glutamic acid and arginine were recorded in both FFS and LFS. In conclusion, the analysis suggested that a fermentation period of 25–30 days showed a significant effect on the composition of amino acids in both types of ensilage compared to other fermentation periods (p < 0.05). Considering the role of amino acids in enhancing the plant growth and proliferation, the findings of the present study are quite useful.