Cellulase producing bacteria were isolated from both soil and ward poultry, using CMC (carboxymethylcellulose) agar medium and screened by iodine method. Cellulase activity of the isolated bacteria was determined by DNS (dinitrosalicylic) acid method. The highly cellulolytic isolates (BTN7A, BTN7B, BMS4 and SA5) were identified on the basis of Gram staining, morphological cultural characteristics, and biochemical tests. They were also identified with 16S rDNA analysis. The phylogenetic analysis of their 16S rDNA sequence data showed that BTN7B has 99% similarity with Anoxybacillus flavithermus, BMS4 has 99% similarity with Bacillus megaterium, SA5 has 99% homology with Bacillus amyloliquefaciens and BTN7A was 99% similar with Bacillus subtilis. Cellulase production by these strains was optimized by controlling different environmental and nutritional factors such as pH, temperature, incubation period, different volumes of media, aeration rate and carbon source. The cellulase specific activity was calculated in each case. In conclusion four highly cellulolytic bacterial strains were isolated and identified and the optimum conditions for each one for cellulase production were determined. These strains could be used for converting plant waste to more useful compounds.
The aim of this study is to construct a new recombinant strain able to degrade cellulose efficiently. The endo-β-1, 3-1, 4 glucanase (bgls) gene was cloned from Bacillus subtilis BTN7A strain by using PCR technique. The specific primers of bgls gene were deduced. Optimization of PCR mixture and program were identified. The nucleotide sequence of bgls was placed in the public domain (GenBank accession number KM009051.1). The obtained bgls DNA was cloned with pGEM®-T Easy Vector. The recombinant plasmid designated as Bgls-NRC-1 was transformed into E. coli DH5α. The successful cloning of the bgls gene was tested either by PCR or by evaluating its expression in its new bacterial host. The bgls gene was expressed efficiently in E. coli and the enzyme activity of the transformant was compared to the enzyme activity of the donor bacterial strain. The new constructs produce much higher enzyme yields than the donor bacterial strain, they produce about 29% and about 57% higher cellulase specific activity at 37 °C and 55 °C respectively. Optimization of cellulolytic activity of the new recombinant strain were described. The effect of minimal medium supplemented with CMC or cellulose, or complete medium (LB) on bgls expression were tested, the order of cellulase activity production was CMC27.2 > cellulose 21.9 > LB 19.8 U/mg protein, respectively at 24 h. CMC was proved to be the best medium for cellulase production. Results also showed that double the initial inoculum resulted in more cellulase activities in all media.
The arbuscular mycorrhizal fungi (AM fungi) as mixture of Glomus spp. was used to induce resistance in Phaseolus vulgaris against root rot disease caused by Rhizoctonia solani. Results showed that % disease incidence was significantly reduced in AMinoculated plants as compared with infected and AM-free control. Production of hydrogen peroxide (H 2 O 2 ) and level of lipid peroxidation increased in both roots and shoots bean plants with increasing the time of infection. AM fungi markedly alleviated oxidative stress in infected bean plants, thus, levels of H 2 O 2 and lipid peroxidation was markedly reduced. Also, activity of antioxidant enzymes (catalase, ascorbate peroxidase and superoxide dismutase) significantly increased in bean tissues in response to both R.solani and/or AM fungus. The highest enzyme activity was recorded in shoots of 14 days old plants inoculated with AM fungi. Total phenolic compounds and various phenolic acids especially cinnamic and ferulic acids greatly increased in roots of bean plants infected with R.solani and/or inoculated with AM fungi. However, coumarin was found only in AM-treated plants. But quercetin markedly increased in bean roots infected by R.solani and decreased in AM-treated plants, as compared with non-infected control. Finally, activity of lignification enzymes (polyphenol oxidase, peroxidase and phenylalanine-ammonia lyase) increased in all infected plants. Our results indicate that AM fungi increased resistance in infected bean plants by inducing both antioxidant system and phenolic compounds pathway.
Endophytic fungi are microorganisms that inhabit the living tissues of their host plants without causing any host loss. They are considered as a continuous natural source of novel bioactive secondary metabolites with potential application in medicine, which are almost same to their host plant. In this study a total of nine endophytic fungal isolates were collected from leaves and stems of Moringa oleifera. Based on the colonization frequency (CF) results, the highest number of isolates was obtained from plant stem, while the least was from leaves. The nine isolates were identified by keeping track of morphological and microscopic observations. Identification of the two antimicrobial potent strains was confirmed by 18S rDNA-based molecular analysis. The nine isolates were found belonging to Chaetomium, Alternaria, Fusarium, Aspergillus, Mycelia, Penicillium and Nigrospora taxa. Among them, Chaetomium taxon was included the highest CF )40% ( . Evaluation of antimicrobial activity documented ethyl acetate fungal extract as the highest effective inhibitor against Gramnegative and Gram-positive bacteria, and Aspergillus fumigatus. Minimum inhibitory concentration (MIC) was examined for the two most potent antimicrobial effective extracts, from Chaetomium laterale and Chaetomium interruptum; it was ranged from 12.5 to 0.39 mg/ml.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.