A xylanase producer Bacillus mojavensis strain, called AG137, isolated from cotton farm (Kashan-Iran). The optimal xylanase activity reached at 55°C & pH 9.0. Enzyme yield was studied using a medium with different agricultural wastes as inducers. Xylanase production of about 249.308 IU/mL was achieved at pH 8 and 37°C, within 48 h submerged fermentation in enzyme production medium supplemented with 2% (w/v) oat bran as an optimum carbon source. A mixture of 1% (w/v) yeast extract and 1% (w/v) tryptone as optimum nitrogen sources, agitation speed 200 rpm, and inoculum size 2% (v/v) were the optimums for maximum production. Accordingly, xylanase yield from 194.68 IU/mL under non-optimized fermentation condition enhanced to 302.466 IU/mL in optimized condition. Screened xylanase is thermostable, presenting 70% stability at 60°C during 30 min. Further enzyme incubation in higher temperature caused a decrease in the residual enzyme activity, yet it retained 68%–50% of its activity after 1 hour from 45°C to 55°C. Besides, it is stable in pH 9 and 10, maintaining over 70% of its activity for 2 h. The enzyme also could preserve 71% and 63% of its initial activity after 3 hours of pre-incubation in the same alkaline condition. Produced xylanase therefore was introduced as an alkaline-active and stable one, displaying suitable thermostability feature, confirmed by HPLC analysis. Hence, all xylanase properties highlight its promising uses in industrial scale.

Background and Aims: Hospital infections and their antibiotic resistance have become a global concern recently. One of the most prominent factors in hospital infections is Pseudomonas aeruginosa (P. aeruginosa), which can become resistant to many antibiotics due to its ability to form biofilms. Recently, scientists have tried to replace antibiotic therapy with alternative therapies such as probiotics which can reduce or eliminate the pathogenic bacteria's ability to form biofilms. Therefore, the present study revealed that some genes, such as algD and PpyR, were involved in biofilm formation in P. aeruginosa. Furthermore, the inhibitory effect of the supernatant of lactobacillus agilis on the biofilm formation of P. aeruginosa was evaluated in the current study. Materials and Methods: In this study, the effect of the supernatant of probiotic Lactobacillus agilis on the biofilm formation of P. aeruginosa and also the expression of two genes effective in biofilm formation (algD and PpyR) were investigated. Antibiograms were performed to detect the most resistant bacteria since there is a link between biofilm formation and antibiotic resistance. Further, the effects of probiotics on the expression of PpyR and algD genes were discussed. Results: Results showed that the biofilm formation of P. aeruginosa was significantly reduced in the presence of lactobacillus agilis. Conclusions: According to the current study, it could be concluded that because of antibiotics resistance and their associated mechanisms, probiotics could be used as a replacement for antibiotics in many treatments.