1. High levan production by Bacillus licheniformis NS032 using ammonium chloride as the sole nitrogen source
- Author
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Vladimir Beškoski, Dragica Jakovljević, J R Stefanovic Kojic, Gordana Gojgić-Cvijović, Marijana Markovic, Miroslav M. Vrvić, and Branka Kekez
- Subjects
0106 biological sciences ,Sucrose ,Daphnia magna ,chemistry.chemical_element ,Bioengineering ,Bacillus ,02 engineering and technology ,01 natural sciences ,Applied Microbiology and Biotechnology ,Biochemistry ,Levan ,Ammonium Chloride ,chemistry.chemical_compound ,Response surface methodology ,010608 biotechnology ,medicine ,Bacillus licheniformis ,Molecular Biology ,EC50 ,biology ,Chemistry ,pH ,Copper toxicity ,General Medicine ,021001 nanoscience & nanotechnology ,medicine.disease ,biology.organism_classification ,Nitrogen ,Acute toxicity ,Fructans ,Yield (chemistry) ,Fermentation ,Ammonium chloride ,Box-Behnken design ,0210 nano-technology ,Copper ,Biotechnology ,Nuclear chemistry - Abstract
In this study, levan production by Bacillus licheniformis NS032 isolated from a petroleum sludge sample was investigated. High levan yield was obtained in a wide range of sucrose concentrations (up to 400 g/L) and, contrary to most levan-producing strains, using ammonium chloride as the sole N source. Interaction between sucrose, ammonium chloride, and initial pH of the medium in a low sucrose (60-200 g/L) and a high sucrose (300-400 g/L) system was analyzed by response surface methodology. According to the calculated model in the low sucrose system, maximum predicted levan yield was 47.8 g/L (sucrose 196.8 g/L, ammonium chloride 2.4 g/L, pH 7.0), while in the high sucrose system, levan yield was 99.2 g/L (sucrose 397.6 g/L, ammonium chloride 4.6 g/L, pH 7.4). In addition, protective effect of microbial levan against copper toxicity to Daphnia magna is observed for the first time. The acute toxicity (48 h EC50) of copper decreased from 0.14 to 0.44 mg/L by levan in concentration of 50 ppm. Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3376]
- Published
- 2014