EVALUATION OF THE ANTIFUNGAL ACTIVITIES OF THREE ESSENTIAL OIL COMPONENTS AGAINST PENICILLIUM EXPANSUM SPORES

Objective: The aim of the present study was to evaluate the antifungal potential of β-Ionone; carvone and 1,8-cineole which are three essential oil components.Methods: For that purpose, the minimum inhibitory (MIC) and fungicidal (MFC) concentrations of these compounds were determined by the microdilution method using the 96 well microtiter plates. The efficiency of these compounds was tested against the spores of Penicillium expansum; a strain responsible for huge post-harvest losses during storage of fruits and capable of producing patulin, a very dangerous mycotoxin for the human health.Results: The obtained results showed a very strong inhibition of the growth of P. expansum spores with very low MIC values determined for β-Ionone (0.625 %); Carvone (0.3125 %) and 1,8-cineol (0.078125 %). In addition, the evaluation of MFCs for the tested essential oil components showed that β-Ionone and carvone molecules exhibited the same MFCs at 5 % against P. expansum spores. However, the best fungicidal activity was found with the 1,8-cineole molecule at a concentration of 1.25 % vis-à-vis of the spores of this strain.Conclusion: This study, which shows for the first time the antifungal potential of these three molecules against this strain, also allows to highlight the possibility of using these essential oil compounds in the formulation of commercial antifungal products

LYCOPENE PRODUCTION IN MYCOBACTERIUM SMEGMATIS BY EXPRESSION OF CRT GENES FROM MYCOBACTERIUM AURUM AND PROTECTIVE EFFECT OF LYCOPENE IN VIVO AND IN VITRO AGAINST UV RADIATION

Objective: The aim of the present study was to express in Mycobacterium smegmatis the clustered mycobacterial genes coding for lycopene synthesis and to investigate the protective properties of lycopene against ultraviolet (UV) irradiation.Methods: The genes, which encode the biogenesis of lycopene in Mycobacterium aurum A+, were introduced into Mycobacterium smegmatis by electroporation. The pigments produced were analyzed by thin layer chromatography, and the absorption spectra were determined. A survival test using UV irradiations was also performed.Results: The transformed Mycobacterium smegmatis were found to synthesize lycopene with important yield (1.41± 3.09 mg/g) and was more resistant to ultraviolet irradiation than non-pigmented strain (p<0.01). Furthermore, cells of M. smegmatis not transformed but coated with lycopene are more resistant to UV than those uncoated (p<0.01).Conclusion: M. smegmatis can form orange colonies on agar plates when it is transformed with the lycopene genes, and the transformants produces 1.41 mg/g (dry weight) of this carotene. Our findings strongly suggest that lycopene has antioxidant activities and prevent the lethal action of UV irradiation on bacterial cells in vivo and in vitro, and deserves further studies considering the amelioration of the production

Investigation of Bacillus pumilus and Staphylococcus haemolyticus adhesion on 304L Stainless Steel in Atmospheric Simulated Medium

The bacteria adhesion on materials surface is the first step to formation of biofilm that could lead to biocorrosion. This study aimed to investigate the correlation between bacteria adhesion and the physicochemical properties of both materials and bacteria in atmospheric simulated medium. The material used in this study is 304L stainless steel and Bacillus pumilus and Staphylococcus haemolyticus bacteria strains. The hydrophobicity, electron donor and electron receptor properties were determined by contact angle measurements. In addition, the bacteria capacity of adhesion was followed by using a scanning electron microscope. The contact angle measurements finding showed that both bacteria have hydrophilic surfaces qualitatively and qualitatively. Otherwise, the stainless steel has revealed a hydrophobic character qualitatively and quantitatively. Moreover, the scanning electron microscope displayed the high speed of adhesion of the studied bacteria. The contact angle measurements could be used as a mean to prevent biocorrosion caused by bacteria adhesion

Microorganisms Isolated fromMoroccan Olive-Mill Wastes: Screening of Their Enzymatic Activities for Biotechnological Use

In this study, three samples of olive oil wastes: Olive Rinse Water (OR), Olive Mill Wastewater (OM) and Olive Pomace (OP), which were collected from an olive oil mill located at Fez-Morocco, were analyzed for their microbiota. A total of 81 isolates were obtained and constituted a microbial bank formed of 35 bacteria, 41 yeasts and 5 fungi. The microbial communities have been compared in term of metabolic potential by testing hydrolytic enzymes activities of lipase, protease, amylase, cellulase, pectinase and tannase on agar plate media. The results reveal that among the examined microorganisms, 68 isolates were able to produce at least one of the screened enzymes. The pectinase activity was the predominant one (39.51%), followed by cellulase activity (34.57%) and by lipase activity (27.16%). However, the amylase activity was observed only for 11.11% of the studied isolates, followed by protease activity (9.88%) and by tannase activity 6.17%. Thereby, considering the isolates ability to produce enzymes, they can be considered as potential candidates for industrial and biotechnological applications. Lipases are versatile enzymes that are used widely, it’s why the mostly aim of this work was to isolate new bacterial strains producing high level of lipases with interesting biochemical criteria. Thus, two isolates OR34 and OM2 showed the maximum lipase production under the standard conditions, about 9 U/ml and 11 U/ml, respectively, using pH-stat technique. They were identified as Proteus vulgaris and Serratia marcescens, respectively, via partial 16S rDNA gene sequence analysis

Biochemical characterization of a thermoactive and thermostable lipase from a newly isolated Trichosporon coremiiforme strain

Nonstop demand for greatly thermostable and thermoactive active lipase encourages the research for the new enzyme sources. In this study, a strain of Trichosporon coremiiforme was isolated from the traditional tannery in the city of Fez in Morocco, lipase production and their lipolytic activity was studied. Pure T. coremiiforme lipase (TCL) was obtained after ammonium sulfate fractionation, G-75 gel filtration and cation exchanger chromatography (Mono-S), having a molecular weight of 67 kDa. TCL presents a maximal activity at pH 8 and 50°C. After a 5 min treatment at 80°C, the enzyme maintained 50% of its activity, which is so far as is known. TCL previously characterized is found to be stable between pH 5 and 10 after 60 min incubation. TCL hydrolyses the long chains triacylglycerols more efficiently than the short ones. A specific activity of 1800 U/mg was measured on tributyrin or olive oil emulsion as substrate. This newly isolated lipase can be considered as a good candidature for industrial and biotechnological applications.Keywords: Trichosporon coremiiforme, lipase, purification, thermoactiveAfrican Journal of Biotechnology Vol. 12(28), pp. 4503-451

Correlation between cell surface physicochemical properties of bacterial strains and their chromium removal potential

Physicochemical characterization of microbes has gained recently a great interest by scientific community. It is proved of extreme importance in several fields of science and technology applications such as bioremediation. In this work, we investigated the establishment of a possible correlation between chromium removal capacity of seven bacterial strains isolated from contaminated sites with industrial wastes including tanning processing and their cell surface physicochemical properties. Thus, hydrophobicity and donor/acceptor electrons character were obtained using contact angle measurements. Statistical analysis showed a high significant positive correlation between hexavalent chromium (Cr(VI)) removal by the strains and their acceptor electron character γ+(r = 0.90). While significant negative correlation between the Cr(VI) removal potential and the ΔGiwi value (r = −0.844) and also with their donor electron character γ− (r = −0.746) were observed. These results may contribute to determine a selectrion criteria of bacteria that can be operated in bioremediation applications

Electrolyte ions and glutathione enzymes as stress markers in Argania spinosa subjected to drought stress and recovery

Understanding the mechanisms underlying Argania spinosa responses to drought stress is essential for its regeneration and domestication. Toward that end, an integrative study of tolerance responses to drought stress in four A. spinosa ecotypes (2 contrasting coastal ecotypes (Adm and Rab) and 2 contrasting inland ecotypes (Alz and Lks)) have been conducted. Responses to soil drying and re -watering were measured at physiological and biochemical levels. Soil drying resulted in significant increase in leaf concentrations of potassium (K+), calcium (Ca2+) and magnesium (Mg2+) with differential responses between ecotypes. The glutathione-related enzymes: glutathione peroxidase (GP), glutathione reductase (GR) and glutathione S-transferase (GST) showed a significant increase in their enzymatic activity in A. spinosa plants subjected to drought stress. Additionally, a significant increase in thiol protein content in the four ecotypes was recorded, during drought stress. These antioxidant traits responded differently depending on ecotype. However, rapid and significant changes in the studied physiological and biochemical traits were observed during recovery from drought, only after four days. According to the traits having the most discriminating power, the both inland ecotypes, especially Lks ecotype, seem to be potential candidates for regeneration of argan forest and their domestication in arid and semi-arid environments.Key words: Argania spinosa, drought stress, glutathione enzymes, thiol compounds, recovery

Effect of phospho-compost and phosphate laundered sludge combined or not with endomycorrhizal inoculum on the growth and yield of tomato plants under greenhouse conditions

The study aims to evaluate the eff ect of endomycorrhizal inoculum (arbuscular mycorrhizal fungi), phospho-compost and phosphate sludge in single (M, PC, PS) or dual combinations (PC+M, PS+M, PS+PC) compared to agricultural and Mamora soils (A and S) on the growth, fl owering, and yield of tomato plants. Among the studied treatments, the substrates containing 5% of phospho-compost combined with endomycorrhizal inoculum (PC+M) gave the most positive eff ect followed by phospho-compost (PC) and endomycorrhizal inoculum (M). In response to PC+M substrate, tomato plant height, the number of leaves and fl owers attained 90 cm, 30, and 25, respectively. In substrates PC and M, tomato plants showed a height of 85 and 75 cm, leaves number of 30 and 19 leave/plant and number of fl owers of 21, and 19 fl ower/plant. An optimal yield with (12 fruits/plant) was recorded in tomato plants grown on the substrate amended with bio-inoculant (AMF) and phospho-compost at a rate of 5%. In terms of qualitative parameters, the highest fresh and dry weight of aerial plant parts and root system were recorded in tomato plants grown in culture substrate incorporating 10 g of endomycorrhizal inoculum and 5% of phospho-compost reaching respectively103.4 g, 34 g 90.1 g, 28.9 g as compared to 87, 51, 23 and 24.1 g noted by tomato plants on the substrate with phospho-compost (5%) (PC). The highest mycorrhization parameters (frequency (F), intensity of mycorrhization (M), average arbuscular content (A), average vesicular content (V), average intraradicular spore content (S)) were found in the roots of tomato plants growing on substrates amended with 5% phospho-compost plus 10 g of endomycorrhizal inoculum, with percentages of 100% F, 61% M, 40.67% A, 18.36% V, and 56.9% S