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( Mouna Bouassida ),( Imen Ghazala ),( Semia Ellouze-chaabouni ),( Dhouha Ghribi ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.1
Biosurfactants or microbial surfactants are surface-active biomolecules that are produced by a variety of microorganisms. Biodegradability and low toxicity have led to the intensification of scientific studies on a wide range of industrial applications for biosurfactants in the field of environmental bioremediation as well as the petroleum industry and enhanced oil recovery. However, the major issues in biosurfactant production are high production cost and low yield. Improving the bioindustrial production processes relies on many strategies, such as the use of cheap raw materials, the optimization of medium-culture conditions, and selecting hyperproducing strains. The present work aims to obtain a mutant with higher biosurfactant production through applying mutagenesis on Bacillus subtilis SPB1 using a combination of UV irradiation and nitrous acid treatment. Following mutagenesis and screening on blood agar and subsequent formation of halos, the mutated strains were examined for emulsifying activity of their culture broth. A mutant designated B. subtilis M2 was selected as it produced biosurfactant at twice higher concentration than the parent strain. The potential of this biosurfactant for industrial uses was shown by studying its stability to environmental stresses such as pH and temperature and its applicability in the oil recovery process. It was practically stable at high temperature and at a wide range of pH, and it recovered above 90% of motor oil adsorbed to a sand sample.
Improvement of Bread Quality and Bread Shelf-life by Bacillus subtilis Biosurfactant Addition
Ines Mnif,Souhail Besbes,Raoudha Ellouze,Semia Ellouze-Chaabouni,Dhouha Ghribi 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.4
The objective of the present work was to determine the effect of the addition of a microorganism derived emulsifier on the quality of bread. The effect of Bacillus subtilis SPB1 biosurfactant has been investigated in comparison to a commercial surfactant, the soya lecithin. Indeed, it led to a better shape and a greater specific volume and voided fraction of loaves. Also, results showed that SPB1 bioemulsifier addition improved considerably the texture profile of bread, mainly at a concentration of 0.075%(w/w). In fact, we showed a notable decrease of firmness, chewiness, and adhesion values with a slight increase of cohesion for bread added emulsifier. According to crumb texture evolution during storage, SPB1 biosurfactant exhibited a significant antistaling effect. Moreover, SPB1biosurfactant addition reduced significantly bread susceptibility to microbial contamination. These results proved that SPB1 biosurfactant could be of a great interest in the bread-making industry.
( Maktouf Sameh ),( Amel Kamoun ),( Claire Moulis ),( Magali Remaud Simeon ),( Dhouha Ghribi ),( Semia Ellouz Chaabouni ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.4
A new Bacillus strain degrading starch, named Bacillus sp. UEB-S, was isolated from a southern Tunisian area. Amylase production using solid-state fermentation on millet, an inexpensive and available agro-resource, was investigated. Response surface methodology was applied to establish the relationship between enzyme production and four variables: inoculum size, moisture-to-millet ratio, temperature, and fermentation duration. The maximum enzyme activity recovered was 680 U/g of dry substrate when using 1.38 × 109 CFU/g as inoculation level, 5.6:1 (ml/g) as moisture ratio (86%), for 4 days of cultivation at 37oC, which was in perfect agreement with the predicted model value. Amylase was purified by Q-Sepharose anion-exchange and Sephacryl S-200 gel filtration chromatography with a 14-fold increase in specific activity. Its molecular mass was estimated at 130 kDa. The enzyme showed maximal activity at pH 5 and 70oC, and efficiently hydrolyzed starch to yield glucose and maltose as end products. The enzyme proved its efficiency for digesting raw cereal below gelatinization temperature and, hence, its potentiality to be used in industrial processes.
Mouna Bouassida,Inès Mnif,Ines Hammami,Mohamed-Ali Triki,Dhouha Ghribi 한국식품과학회 2023 Food Science and Biotechnology Vol.32 No.11
Bacillus subtilis SPB1 derived biosurfactants (BioS) proved its bio-control activity against Agrobacterium tumefaciens using tomato plant. Almost 83% of disease symptoms triggered by Agrobacterium tumefaciens were reduced. Aiming potential application, we studied lipopeptide cost-effective production in both fermentations systems, namely the submerged fermentation (SmF) and the solid-state fermentation (SSF) as well as the use of Aleppo pine waste and confectionery effluent as cheap substrates. Optimization studies using Box–Behnken (BB) design followed by the analysis with response surface methodology were applied. When using an effluent/sea water ratio of 1, Aleppo pine waste of 14.08 g/L and an inoculum size of 0.2, a best production yield of 17.16 ± 0.91 mg/g was obtained for the SmF. While for the SSF, the best production yield of 27.59 ± 1.63 mg/g was achieved when the value of Aleppo pine waste, moisture, and inoculum size were, respectively, equal to 25 g, 75%, and 0.2. Hence, this work demonstrated the superiority of SSF over SmF.