Characterization of the biosurfactant production and enzymatic potential of bacteria isolated from an oil-contaminated saline soil / Caracterización de la producción de biosurfactantes y potencial enzimático de bacterias aisladas de un suelo salino contaminado con aceite

Biosurfactants are amphiphilic compounds with extensive applications in oily contaminated environments to remove hydrocarbons. Moreover, enzymes such as laccase and manganese peroxidase are responsible for the oxidation of a variety of phenolic compounds and aromatic amines. Therefore, in the present study, bacteria with the potential to produce biosurfactants and enzymes (namely, laccase, manganese peroxidase, and endoglucanase carboxymethyl cellulose (CMCase)) were isolated from petroleum oil-contaminated soil. From 15 isolated bacteria, three isolates were selected as the best producers of biosurfactants according to the related tests, such as tests for surface tension reduction. These three bacteria indicated tolerance to a salinity test and were classified as resistant and very resistant. The isolates 3, 12, 13, and 14 showed positive results for the degradation of guaiacol, phenol red, and carboxymethylcellulose, as well as the decoloration of methylene blue by the creation of a clear halo around the bacterial colony. Upon the quantitation of the laccase and manganese peroxidase activities, 22.58 U/L and 21.81 U/L, respectively, were measured by isolate 13. Furthermore, CMCase activity was recorded with 0.057436 U/ml belonging to isolate 14. Bacterial strains with appreciable laccase, peroxidase, CMCase activity, and biosurfactant production potentials were identified through 16S rDNA sequence analysis as Bacillus sp. (isolate 3), Bacillus toyonensis (isolate 12), Bacillus cereus (isolate 13), and Bacillus tropicus (isolate 14), and their nucleotide sequences were deposited in the GenBank. The potentials for the industrial applicability of the biosurfactants and enzymes abound, and production needs to be optimized by the selected bacterial strains.(AU)

Characterization of the biosurfactant production and enzymatic potential of bacteria isolated from an oil-contaminated saline soil.

Biosurfactants are amphiphilic compounds with extensive applications in oily contaminated environments to remove hydrocarbons. Moreover, enzymes such as laccase and manganese peroxidase are responsible for the oxidation of a variety of phenolic compounds and aromatic amines. Therefore, in the present study, bacteria with the potential to produce biosurfactants and enzymes (namely, laccase, manganese peroxidase, and endoglucanase carboxymethyl cellulose (CMCase)) were isolated from petroleum oil-contaminated soil. From 15 isolated bacteria, three isolates were selected as the best producers of biosurfactants according to the related tests, such as tests for surface tension reduction. These three bacteria indicated tolerance to a salinity test and were classified as resistant and very resistant. The isolates 3, 12, 13, and 14 showed positive results for the degradation of guaiacol, phenol red, and carboxymethylcellulose, as well as the decoloration of methylene blue by the creation of a clear halo around the bacterial colony. Upon the quantitation of the laccase and manganese peroxidase activities, 22.58 U/L and 21.81 U/L, respectively, were measured by isolate 13. Furthermore, CMCase activity was recorded with 0.057436 U/ml belonging to isolate 14. Bacterial strains with appreciable laccase, peroxidase, CMCase activity, and biosurfactant production potentials were identified through 16S rDNA sequence analysis as Bacillus sp. (isolate 3), Bacillus toyonensis (isolate 12), Bacillus cereus (isolate 13), and Bacillus tropicus (isolate 14), and their nucleotide sequences were deposited in the GenBank. The potentials for the industrial applicability of the biosurfactants and enzymes abound, and production needs to be optimized by the selected bacterial strains.

Enzymatic hydrolysis of Opuntia ficus-indica cladode by Acinetobacter pittii and alcohol fermentation by Kluyveromyces marxianus: pH, temperature and microorganism effect.

In the present work the effect of three factors: pH, temperature and type of microorganism using a factorial design 32x2 was evaluated on: growth, total cellulases hydrolytic activity (FPases), endoglucanases hydrolytic activity (CMCases), free reducing sugars (FRS), glucose, sucrose, and alcohol production using a culture medium based on mineral salts added with cladodes flour of Opuntia ficus-indica at 20% as the unique carbon source. Two wild microorganisms were used, Acinetobacter pittii a bacteria isolated from decaying cladodes, and Kluyveromyces marxianus a yeast isolated from termite stomach. The maximum hydrolytic activities were obtained with Acinetobacter pittii at 37 °C and pH 6.5 for total cellulases (0.67 ±â€¯0.02 IU/ml) and for endoglucanases (0.23 ±â€¯0.02 IU/ml) at 24 and 4 h. The maximum production of alcohol was 12.98 ±â€¯0.06 g/L obtained with Kluyveromyces marxianus at 4 h with conditions of 40 °C and pH 5.5.

Nutritional Intake by Ectoplasmic Nets of Schizochytrium aggregatum (Labyrinthulomycetes, Stramenopiles).

Thraustochytrid cells attach to their food via ectoplasmic nets (ENs). Here, we analyzed the cause and effect relationship between the various forms and functions of ENs of Schizochytrium aggregatum. The ENs spread out over a large area forming a fine network to efficiently search for the experimental food source. After recognizing the experimental food source, the ENs that attached to the food source became thicker, and net elements developed. The thick ENs on the surface at the attachment site were enveloped in dense materials (fibrous materials), which were visualized as fibrous layers under a transmission electron microscope. Experiments using fluorescein diacetate and the fluorescent glucose analog 2-NBDG showed that the production rate of hydrolytic enzymes and the absorption rate of glucose by ENs of S. aggregatum increased in the presence of an experimental food source. Our results reveal that ENs change their shape and function according to the presence/absence of a food source.

Isolation and Identification on a Thermoacidophilic Fungus of High-producing Cellulase and the Characteristics of its Enzyme / 微生物学通报

A novel Aspergillus terreus strain M11 was isolated from the compost containing cellulose and identified. The isolate grow best at 45℃ and pH2.0. It was found that the activity of the CMCase was up to 3.680IU/mL with high heat stability and the optimal reaction conditions of the CMCase were at 60℃ and pH2.0.