Search

Biodegradation of reactive azo dyes has been an arduous problem for decades. Several efficient biosystems have been proposed for dye degradation, but most of them are dependent on the availability of costly co-substrates such as peptone, yeast extract, and/or glucose. The present study describes the azo dye degradation by a bacterial consortium using glycerol as a sole co-substrate. The consortium was developed from a mixed bacterial culture obtained upon enrichment of soil sediment for Reactive Blue 28 (RB28) decolorization in the presence of glycerol (0.1%; v/v). The consortium with three bacterial species, i.e., Stenotrophomonas acidaminiphila APG1, Cellulomonas sp. APG4, and Pseudomonas stutzeri APG2, designated as “SCP,” decolorized 92% of 100 ppm dye in 96 h. The intricacies of the interactions existing within the members of the consortium were resolved by a simple and unique analysis called “BSocial.” Among all the members, Cellulomonas sp. APG4 exerted a net-positive impact for decolorization (%) on the consortium. The net fitness of the community increased when all the three species were present, and thus, all of them were selected for further analysis. Moreover, APG4 seemed to be central in the reductive decolorization as it possessed the highest reductase activity. The dye degradation by the consortium was demonstrated by UV-Visible spectroscopy, HPTLC, and FTIR spectroscopy of control and decolorized cell-free supernatant. The LC-ESI-MS analysis of metabolites extracted from decolorized cell-free medium led to the identification of degradation products, thus leading us to propose the plausible pathway for degradation of RB28 by bacterial consortium. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s42770-020-00303-3) contains supplementary material, which is available to authorized users.

AIMS Lignocellulosic biomass deconstruction is a bottleneck for obtaining biofuels and value-added products. Our main goal was to characterize the secretome of a novel isolate, Cellulomonas sp. B6, when grown on residual biomass for the formulation of cost-efficient enzymatic cocktails. METHODS AND RESULTS We identified 205 potential CAZymes in the genome of Cellulomonas sp. B6, 91 of which were glycoside hydrolases (GH). By secretome analysis of supernatants from cultures in either extruded wheat straw (EWS), grinded sugar cane straw (SCR) or carboxymethylcellulose (CMC), we identified which proteins played a role in lignocellulose deconstruction. Growth on CMC resulted in the secretion of two exoglucanases (GH6 and GH48) and two GH10 xylanases, while growth on SCR or EWS resulted in the identification of a diversity of CAZymes. From the 32 GHs predicted to be secreted, 22 were identified in supernatants from EWS and/or SCR cultures, including endo- and exoglucanases, xylanases, a xyloglucanase, an arabinofuranosidase/β-xylosidase, a β-glucosidase and an AA10. Surprisingly, among the xylanases, seven were GH10. CONCLUSIONS Growth of Cellulomonas sp. B6 on lignocellulosic biomass induced the secretion of a diverse repertoire of CAZymes. SIGNIFICANCE AND IMPACT OF THE STUDY Cellulomonas sp. B6 could serve as a source of lignocellulose-degrading enzymes applicable to bioprocessing and biotechnological industries.

Novel 1H-pyrazolo[3,4-b]quinoxalines (flavazoles) 14, 15 and 1-aryl-3-quinoxalinyl-1,2,4-triazole 17 were synthesized from the ester 11 via various hydrazones 12, 13 and 16. In the antibacterial screening test of compounds 12–17, compound 14 showed a relatively high antibacterial activity, wherein the MIC value was 25 μg/ml against Bacillus licheniformis KTCC 21425 and Cellulomonas sp. and 50 μg/ml against Salmonella typhimurium KCTC 1925 and Flavobacterium devolans.

Two-hundred and twenty-five mangrove bacterial strains previously isolated from several mangrove areas in the Philippines were qualitatively screened for cellulase production and 154 were found to be capable of cellulase production. Among them, ten strains showed very strong positive cellulase activities, which were then quantified. Five with the statistically highest activities, specifically, BBCS-11, BBCS-14, BBoB2L2-2, BOrMGS-2, and BOrMGS-3, including Cellulomonas sp. BIOTECH 1240 (control), were further subjected to partial optimization studies. The effects of substrate, pH, incubation temperature and incubation time on cellulase productoin were determined. The cellulase activities (U mL -1 ) of the strains under optimized conditions were: 54.80 (Control); 56.60 (BBCS-11); 66.50 (BBCS-14); 50.33 (BBoB2L2-2); 51.04 (BOrMGS-2); and 48.70 (BOrMGS-3). The promising cellulase producers were previously identified: BBCS-11 as Bacillus cereus; BBCS-14 as Bacillus licheniformis; BOrMGS-2 and BOrMGS-3 as Bacillus pumilus; and BBoB2L2-2 as Bacillus sp.

Cellulose degrading bacteria were isolated from the intestinal fluid of the silver cricket Lepisma Sp. and a culture was developed anoxigenically in the cellulose degrading medium following standard laboratory techniques. The cellulolytic activity of the microbe was examined in a broth culture using Whatman 42 filter paper as the source of insoluble cellulose. Activity was measured spectrophotometrically (620nm) following Anthrone reaction of the culture filtrate and the sugar produced was quantified as a factor of time. The pH optimum was found to be between 7 and 8. Temperature profile optimum was between 30–37°C. The microbes appeared as white colonies on a solid medium. Morphologically the bacterium is a gram-positive nonspore forming rod which was tentatively identified as a new strain of Cellulomonas sp.

The reduction of Cr(VI), Fe(III), and U(VI) was studied using three recently isolated environmental Cellulomonas sp. (WS01, WS18, and ES5) and a known Cellulomonas strain ( Cellulomonas flavigena ATCC 482) under anaerobic, non-growth conditions. In all cases, these cultures were observed to reduce Cr(VI), Fe(III), and U(VI). In 100 h, with lactate as electron donor, the Cellulomonas isolates (500 mg/l total cell protein) reduced nitrilotriacetic acid chelated Fe(III) [Fe(III)-NTA] from 5 mM to less than 2.2 mM, Cr(VI) from 0.2 mM to less than 0.001 mM, and U(VI) from 0.2 mM to less than 0.12 mM. All Cellulomonas isolates also reduced Cr(VI), Fe(III), and U(VI) in the absence of lactate, while no metal reduction was observed in either the cell-free or heat-killed cell controls. This is the first report of Cellulomonas sp. reducing Fe(III) and U(VI). Further, this is the first report of Cellulomonas spp. coupling the oxidation of lactate, or other unknown electron donors in the absence of lactate, to the reduction of Cr(VI), Fe(III), and U(VI).

A cellulolytic bacterium has been isolated from soil and identified as a Cellulomonas sp. Optimization of media components and environmental factors led to a 17-fold increase in cellulase activity within 40 h. The trace elements Zn2+, Co2+ and Cu2+ caused severe inhibition, which could be reduced by the addition of EDTA. The enzymes endoglucanase, exoglucanase and xylanase were always present irrespective of the carbon source used.

The distribution of glycerol dehydrogenase activity was studied with cell-free extracts of bacteria, yeasts, molds and actinomycetes. High activity was found in 4 strains of bacteria and in 3 strains of molds. The enzymes of bacteria were dependent on NAD+ and those of molds were dependent on NADP+. An isolated gram-positive bacterium, which showed the high activity, was identified as Cellulomonas sp. NT3060. The total and specific activities were associated with growth of this strain and reached the maximum at the early stationary phase. Significant high level activity was detected in cell-free extracts from glycerol and glucose media.

A culture of Cellulomonas sp. and Bacillus subtilis was grown using sugar cane bagasse pith from unburnt sugar cane (UCP) as the source of carbohydrates. The yield and production values were proved to be higher than those obtained with burnt sugar cane (BCP).

Six major components exhibiting endo-1,4-\-d-glucanase activity were partially purified from culture filtrates of a newly isolated Cellulomonas sp. using ion-exchange chromatography. Molecular weights (44,000 to 140,000), pH optima (6.0 to 7.0), temperature optima (40 to 50°C), half-life, energy of activation, Kmand other kinetic parameter investigations indicate the existence of 6 different endoglucanases. Further support for this assumption comes from inhibition studies, whereby glucose inhibited the enzyme activities between 15 and 50% at a concentration of 0.034% (1.65 mM) and cellobiose between 0 and 50% at a concentration of 0.1% (2.92 mM). Of all the metals (Hg2+, Co2+, Cu2+, Ca2+, Mg2+, Zn2+, Fe3+) tested, only Hg2+ exhibited a 55% inhibition at 5.0 mM.

Steady-state continuous culture was used to optimize lean chemically defined media for a Cellulomonas sp. and Bacillus cereus strain T. Both organisms were extremely sensitive to variations in trace-metal concentrations. However, medium optimization by this technique proved rapid, and multifactor screening was easily conducted by using a minimum of instrumentation. The optimized media supported critical dilution rates of 0.571 and 0.467 h −1 for Cellulomonas and Bacillus , respectively. These values approximated maximum growth rate values observed in batch culture.