Characterization of lignin and hemicellulose degrading bacteria isolated from cow rumen and forest soil: Unveiling a novel enzymatic model for rice straw deconstruction.

Application of greener pretreatment technology using robust ligninolytic bacteria for short duration to deconstruct rice straw and enhance bioethanol production is currently lacking. The objective of this study is to characterize three bacterial strains isolated from the milieux of cow rumen and forest soil and explore their capabilities of breaking down lignocellulose - an essential process in bioethanol production. Using biochemical and genomic analyses these strains were identified as Bacillus sp. HSTU-bmb18, Bacillus sp. HSTU-bmb19, and Citrobacter sp. HSTU-bmb20. Genomic analysis of the strains unveiled validated model hemicellulases, multicopper oxidases, and pectate lyases. These enzymes exhibited interactions with distinct lignocellulose substrates, further affirmed by their stability in molecular dynamic simulations. A comprehensive expression of ligninolytic pathways, including ß-ketoadipate, phenyl acetate, and benzoate, was observed within the HSTU-bmb20 genome. The strains secreted approximately 75-82 U/mL of cellulase, xylase, pectinase, and lignin peroxidase. FT-IR analysis of the bacterial treated rice straw fibers revealed that the intensity of lignin-related peaks decreased, while cellulose-related peaks sharpened. The values of crystallinity index for the untreated control and the treated rice straw with either HSTU-bmb18, or HSTU-bmb19, or HSTU-bmb20 were recorded to be 34.48, 28.49, 29.36, 31.75, respectively, which are much higher than that of 13.53 noted for those treated with the bacterial consortium. The ratio of fermentable cellulose in rice straw increased by 1.25-, 1.79-, 1.93- and 2.17-fold following treatments with HSTU-bmb18, HSTU-bmb20, HSTU-bmb19, and a mixed consortium of these three strains, respectively. These aggregative results suggested a novel model for rice straw deconstruction utilizing hydrolytic enzymes of the consortium, revealing superior efficacy compared to individual strains, and advancing cost-effective, affordable, and sustainable green technology.

Terpenoids and phytosteroids isolated from Commelina benghalensis Linn. with antioxidant activity.

Background Commelina benghalensis Linn. (Family: Commelinaceae) is a common weed available in Bangladesh with several uses in traditional medicine. However, the chemical profile of this medicinal plant is scarce in relation to its medicinal uses. The aerial parts of this plant have been investigated for the isolation of secondary metabolites and evaluation of the biological activities. Methods Major phytochemical groups were analyzed using chromogenic reagents, whereas n-hexane soluble fractionates of the methanol extract were subjected to 1H nuclear magnetic resonance (NMR) spectroscopic analysis. The antioxidant property of the obtained compounds was evaluated using 1,1-diphenyl-2-picryl-hydrazyl (DPPH). Results Dammara-12-en-3-one (CB-1), stigmasterol (CB-2) and 3 (2,3,4,5,6-pentahydroxy)-cinnamoyl dammara-12-ene (CB-3) were isolated from the n-hexane fractionate of methanol extract of C. benghalensis. In the study of DPPH radical scavenging activity, IC50 values were predicted to be 790.18, 4186.94 and 2001.16 µg/mL for CB-1, CB-2 and CB-3, respectively, whereas standard ascorbic acid showed IC50 at 1.26 µg/mL. Conclusions Two new dammarane-type triterpene (CB-1 and CB-3) and one phytosterol (CB-2) were identified in C. benghalensis with mild antioxidant property.

Phase behavior of poly(oxyethylene) cholesteryl ether/novel alkanolamide/water systems.

The phase behavior and microstructure of mixed nonionic surfactant systems containing poly(oxyethylene) cholesteryl ether (ChEOn, n=15 and 10), a new alkanolamide-type foam booster, dodecanoyl N -methylethanolamide (NMEA-12), and water, were investigated at 25 degrees C by means of visual observation and small-angle X-ray scattering. In the ChEO(15)/water binary system, aqueous micellar (W(m)), discontinuous cubic liquid crystal (I(1)), hexagonal (H(1)), rectangular ribbon (R(1)), lamellar (L(alpha)), and solid (S) phases are successively formed with increasing surfactant concentration. Although the R(1) phase is an intermediate phase formed in a very narrow composition range in conventional surfactant systems, its domain is unusually wider than that of H(1), which may be attributed to the packing constraint caused by the bulky cholesteric group in the lipophilic core of the aggregate. Upon addition of lipophilic NMEA-12 to the ChEO(15)/water binary system, the interfacial curvature of the aggregates decreases, and the micellar or liquid crystal phases formed in the binary system transform to the reverse micellar (O(m)) phase via the L(alpha) phase existing over a wide concentration range. The SAXS results establish an epitaxial relationship between the (11) plane of the R(1) phase and the (10) plane of the L(alpha) phase. The ChEO(10)/NMEA-12/water system shows a phase diagram of similar general appearance, except that the W(m) to R(1) phase transformation occurs via an optically anisotropic liquid crystal phase of unknown structure and the R(1) to L(alpha) phase transition occurs through a narrow intermediate defected lamellar (L(alpha)(H)) phase. The variation in the aggregate size and shape and the unit cell of the R(1) phase formed in ChEOn/NMEA-12/water systems is also discussed.