Aims: To isolate and characterize lignocellulase producing thermophilic bacteria from a Peruvian hot spring. Study Design: Combined sediment and water samples from the hot spring were subjected to direct plating, in situ baiting and ex situ enrichment. Endoglucanase and xylanase producing bacterial colonies were isolated and characterized. Place and Duration of Study: Samples were taken from the Huancarhuaz hot spring, Peru (8º56'31.86"S, 77º47'00.53"W) in August 2010 and processed during 2011-2013.Methodology: Samples were subjected to three isolation methods and bacterial colonies with different color, size and appearance, were isolated, purified by streaking several times and conserved in Tryptic Soy Agar slants at 4ºC. The agar staining method was used to isolate enzyme-producing strains which were then identified by 16S rRNA sequencing and further studied for endoglucanase and xylanase production.

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It was isolated bacteria strains from three different types of samples: fresh water, in situ baits and ex situ enrichment. Serial dilutions were prepared and culture was carried at 50 °C using a Basal-Saline medium. Isolated strains were screened for endoglucanase and xylanase activities with qualitative (Congo Red) and quantitative (DNS) methods. Molecular 16S rDNA sequencing analysis was performed for taxonomic identification. It was isolated 31 strains of which 14 showed hydrolytic activities and belonged to Bacillus subtilis and Bacillus licheniformis species. Moreover, the strain B. subtilis DCH4 showed the highest endoglucanase activity at 45°C and pH 5, and xylanase activity at 55°C and pH 6. Then, DCH4 was cultivated by submerged fermentation with two different media supplemented with sugar cane bagasse, wheat straw, or quinoa stalk to evaluate its saccharification capability. Likewise, it was screening its xylanase and cellulase genes employing specific primers; the amplicons obtained were sequenced, and analyzed. It was found that, enzymatic extracts of DCH4 prepared with cane bagasse or quinoa stalk media achieved the highest endoglucanase and xylanase activities. According to molecular analysis of genes involved in the hydrolytic process, the endoglucanase and xylanase activities exhibited by DCH4 could be attributed to a bifunctional cellulase conformed by endo-beta-1,4-glucanase (GH5) joined to cellulose binding domain 3 (CBM3), and an endo-1,4-beta-xylanase (GH11), respectively. Further transcriptomic experiments would be considered to accomplish optimization strategies for biofuel production from lignocellulosic biomass.

Four indole-3-carbaldehyde semicarbazone derivatives, 2-((5-bromo-1H-indol-3-yl)methylene)hydrazinecarboxamide (1), 2-((5-chloro-1H-indol-3-yl)methylene)hydrazinecarboxamide (2), 2-((5-methoxy-1H-indol-3-yl)methylene)hydrazinecarboxamide (3), and 2-((4-nitro-1H-indol-3-yl)methylene)hydrazinecarboxamide (4) were synthesized and characterized by ESI-MS and spectroscopic (FT-IR, 1H NMR, and 13C NMR) techniques. The two-dimensional NMR (in acetone-d6) spectral data revealed that the molecules 1 and 2 in solution are in the cisE isomeric form. This evidence is supported by DFT calculations at the B3LYP/6-311++G(d,p) level of theory where it was shown that the corresponding most stable conformers of the synthesized compounds have a cisE geometrical configuration, in both the gas and liquid (acetone and DMSO) phases. The in vitro antibacterial activity of compounds 1–4 was determined against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria. Among all the tested semicarbazones, 1 and 2 exhibited similar inhibitory activities against Staphylococcus aureus (MIC = 100 and 150 μg/mL, respectively) and Bacillus subtilis (MIC = 100 and 150 μg/mL, respectively). On the other hand, 3 and 4 were relatively less active against the tested bacterial strains compared with 1, 2, and tetracycline.