Representatives Of Bacillus Research Articles

Isolation and characterization of Bacillus sp. IMV B-7883 proteases

The representatives of Bacillus are some of the best protease producers studied so far since they exhibit broad substrate specificity, significant activity, stability, simple downstream purification, short period of fermentation and low cost. Earlier, we showed that Bacillus sp. IMV B-7883 strain synthesizes an extracellular proteases, which exhibit elastolytic and fibrinogenolytic activity. The aim of the work was to isolate and purify these enzymes from the culture liquid of the Bacillus sp. IMV B-7883 strain, as well as to study their properties. Isolation and purification of proteases was carried out by precipitation of the culture liquid with ammonium sulfate, gel permeation and ion exchange chromatography and rechromatography on Sepharose 6B. As a result, proteases with elastolytic and fibrinogenolytic activity with a molecular weight of 23 and 20 kDa respectively were isolated with elastase activity increased by 63.6 and fibrinogenolytic activity by 44.1 times. The enzyme with elastase activity had a pH-optimum of 7.0 and hydrolyzed only elastin, while the enzyme with fibrinogenolytic activity was an alkaline protease with a pH-optimum of 8.0 and in addition to fibrinogen, showed specificity for fibrin and, in trace amounts, for collagen. Keywords: Bacillus sp. IMV B-7883, elastase, fibrinogenase, pH optimum, substrate specificity

Bacterial endophytes diversity of tree legumes from Argentina

The aim of this work was to isolate and characterize, based on microbiological as well as molecular markers, bacteria within nodules of three native trees species from South America: Poecilanthe parviflora Benth (Lapachillo), Vachellia caven (Molina) Seigler & Ebinger (Espinillo), and Enterolobium contortisiliquum (‎Vell.‎) ‎Morong (Timbó). In line with this, we isolated and characterized 15 bacteria from P. parviflora, 6 from V. caven and 1 from E. contortisiliquum. Among them we identified representatives of Bradyrhizobium sp. from E. contorsiliquum and P. parviflora, as well as of Ensifer sp. (Sinorhizobium) and Mesorhizobium sp. from V. caven. Also, other bacteria were found, like representatives of Bacillus sp., Microbacterium sp. and Curtobacterim sp., as well as Caulobacter sp., Dyella sp., Pseudomonas sp. and Enterobacter sp. Some of these isolates inhibited the growth of two fungal plant pathogens. So, nodules of these native legumes not only are occupied by highly diverse rhizobia but also by other bacteria that might promote plant growth.

Microbial Consortium with High Cellulolytic Activity (MCHCA) for Enhanced Biogas Production.

The use of lignocellulosic biomass as a substrate in agricultural biogas plants is very popular and yields good results. However, the efficiency of anaerobic digestion, and thus biogas production, is not always satisfactory due to the slow or incomplete degradation (hydrolysis) of plant matter. To enhance the solubilization of the lignocellulosic biomass various physical, chemical and biological pretreatment methods are used. The aim of this study was to select and characterize cellulose-degrading bacteria, and to construct a microbial consortium, dedicated for degradation of maize silage and enhancing biogas production from this substrate. Over 100 strains of cellulose-degrading bacteria were isolated from: sewage sludge, hydrolyzer from an agricultural biogas plant, cattle slurry and manure. After physiological characterization of the isolates, 16 strains (representatives of Bacillus, Providencia, and Ochrobactrum genera) were chosen for the construction of a Microbial Consortium with High Cellulolytic Activity, called MCHCA. The selected strains had a high endoglucanase activity (exceeding 0.21 IU/mL CMCase activity) and a wide range of tolerance to various physical and chemical conditions. Lab-scale simulation of biogas production using the selected strains for degradation of maize silage was carried out in a two-bioreactor system, similar to those used in agricultural biogas plants. The obtained results showed that the constructed MCHCA consortium is capable of efficient hydrolysis of maize silage, and increases biogas production by even 38%, depending on the inoculum used for methane fermentation. The results in this work indicate that the mesophilic MCHCA has a great potential for application on industrial scale in agricultural biogas plants.

Degradation and Metabolization of Lindane and Other Hexachloro- cyclohexane Isomers by Anaerobic and Aerobic Soil Microorganisms

Abstract Microbial Metabolization of Hexachlorocyclohexane, Anaerobic and Aerobic Microorganisms, Dechlorination of Hexachlorocyclohexane Microbial degradation of lindane or other hexachlorocyclohexane isomers has been observed to occur more rapidly in flooded than in upland soils. Experiments with a mixed bacterial flora enrich­ ed anaerobically from soils showed a rapid dechlorination and degradation of lindane. Screening studies with pure bacteria indicated that Clostridium spp. and several representatives of Bacillus spp. and Enterobacteriaceac effectively degraded lindane, while representatives of Lactobacillaceae and Propionibacterium were inactive. During degradation organic bound chlorine was released as chloride and nearly chlorine-free, partly volatile metabolites were formed. The chloride formation was promoted by the addition of glucose, pyruvate or formate. Lindane was the most easily degraded isomer, while α-and especially β-and δ-hexachlorocyclo-hexane was also, but more slowly, dechlorinated. These isomers are relatively frequently observed as environmental contaminants, their occurrence might be caused by their greater persistence or / and by an isomerization of the γ-into α-and other isomers during microbial incubation as it was discussed by several authors. Experiments, however, whether or not this isomerization can be carried out by microbes, were negative or showed that it only can occur to a very minor extent. Aerobic degradation of lindane proceeded only slowly and chiefly by formation of chlorinated aromatic compounds. One of the main intermediate metabolites seemed to be γ-pentachlorocyclo-hexene which was further transformed by the release of HCl or hydrogen and by addition of water. During anaerobic incubation, γ-tetrachlorocyclohexene intermediately occurred which was further dechlorinated to nearly chlorine-free compounds.