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The production of extremozymes from halophilic bacteria has increased significantly due to their stability and efficiency in catalyzing a reaction, as well as their capacity to display optimum activity at various salt concentrations. In the current study, the halophilic bacterium Virgibacillus salarius strain BM-02 could utilize many non-pretreated substrates including cellulose, corn stover, sugarcane bagasse and wheat bran as a sole carbon source. However, wheat bran was the best substrate for achieving optimum saccharification yield (90.1%). The partially purified cellulase was active and stable at a wide range of pH (5–8) with residual activities > 58%. Moreover, it was stable at 5–12% of NaCl. Metal ions have a variable impact on the activity of partially purified cellulase however, Fe+3 exhibited the highest increase in the cellulase activity. The enzyme exhibited a thermal stability at 40, 50 and 60 °C with half-lives of 1049.50, 168.14 and 163.5 min, respectively. The value of Vmax was 22.27 U/mL while Km was 2.1 mM. The activation energy of denaturation Ed 69.81 kJ/mol, the enthalpy values (ΔHd) were positive, and the entropy values (ΔS) were negative. Therefore, V. Salarius is recommended as a novel promising halophilic extremozyme producer and agricultural waste remover in the bio-industrial applications. [ABSTRACT FROM AUTHOR] more...

Plant Growth-Promoting Rhizobacteria (PGPR) inhabiting the area around the plant roots or in plant tissues and stimulate plant growth directly or indirectly. Synthesis of the phytohormone auxin indole-3-acetic acid (IAA) is one of the direct effects of PGPR on plant growth. This study aimed to isolate and screen IAA producing bacteria from soil and study the impacts of the alkalinity and salinity on IAA production and total antioxidant activity of the highly IAA producing strain. From the fifteen isolates tested, six were selected as efficient IAA producer, from which one isolate was highly IAA producer. The highly producing isolate was identified based on molecular characteristics using 16S rRNA. The sequence analysis showed 99% similarity with Bacillus subtilis from GenBank data base. The strain yielded IAA in a wide range of pH (5-9), giving its maximum IAA production at pH 8. High IAA concentration was also observed in the presence of 0.5% and 1% NaCl in comparison with control (with no NaCl). Furthermore, the results indicated that, total antioxidant was increased in acidic (pH 5 and pH 6) and alkaline (pH 8) media, as well as in salinity up to 2%. This study could be stated as the prospective of IAA producing bacterial isolate in the field, as a result, using it as alternative valuable biofertilizer. [ABSTRACT FROM AUTHOR] more...