Production of laccase without inducer by Chaetomium species isolated from Chettaba forest situated in the East of Algeria

A positive laccase strain which showed a positive reaction with guaïacol was isolated from Chettaba Forest, which is situated in Constantine, the East of Algeria. It was identified as Chaetomium species (Ref 051A) according to the morphological and ribosomal internal transcribed spacer (ITS) DNA genomic sequence analysis. Laccase activity was determined by using 2,2-azinobis(3- ethylbenzthiazoline-6-sulfonate) diammonium salt (ABTS) as a substrate. Its highest activity was achieved by using potato dextrose broth (PDB) as a culture medium. Metal ion CuSO4 had no positive effect on laccase production. The laccase activity obtained in submerged fermentation (20 L) was higher than that produced in Erlenmeyer flask (500 ml). The study of pH and temperature effects showed that pH optimum was 5 and 6, and temperature was 35°C. Laccase produced by Chaetomium spp. can be used in industrial production.Keywords: Chaetomium species, guaïcol, laccase, 2,2-azinobis(3- ethylbenzthiazoline-6-sulfonate) diammonium salt (ABTS), submerged fermentatio

Flow cytometry approach for studying the interaction between Bacillus mojavensis and Alternaria alternata

Tomato, Solanum lycopersicum is one of the most important vegetable crops consumed in Algeria. Tomato crops are often infected by Alternaria alternata, which causes early blight disease. Chemical pesticides are intensively used to protect this plant, which lead to environmental pollution that might endanger animal and human health. The main objective of this study is to select potential biocontrol agents from arid soil as an alternative to chemical products. The phytopathogenic fungus which was isolated from infested tomato leaves, stems and fruits cultured in Constantine-Algeria, was identified as Alternaria cf. alternata. Thirty five bacteria isolates were obtained from arid soil in the south of Algeria. Three of the isolates inhibited the growth of A. alternata. However, the most potent isolate, E1B3 reached a 75% inhibition rate. The molecular identification of this isolate showed that it was closely related to Bacillus mojavensis (KC977492). This strain does not produce chitinase, but does produce lipase, protease and lipopeptides. The interaction between A. alternata and B. mojavensis was investigated for the first time in this work by flow cytometric analysis. In conclusion, B. mojavensis strain was antagonistic to A. alternata which could possibly be exploited as a biopesticide in tomato crops management.Keywords: Tomato, Bacillus mojavensis, early blight, Alternaria alternata, flow cytometr

A new record of Agaricus litoralis, a rare edible macro-fungus from Eastern Algeria

A rare edible macro-fungus of phylum Basidiomycota belonging to the genus Agaricus (Agaricales, Agaricomycetes) was collected at the forest of Djebel el Ouahech of Constantine region in the eastern of Algeria and was identified as Agaricus litoralis using morphological and molecular Data. The species Agaricus litoralis is reported for the first time in Algeria

Chemical Composition of Aspergillus creber Extract and Evaluation of its Antimicrobial and Antioxidant Activities

Among the species belonging to the Aspergillus section Versicolores, Aspergillus creber has been poorly studied and still unexplored for its biological activities. The present study was undertaken to analyze A. creber extract and to evaluate its in vitro antimicrobial and antioxidant activities. UHPLC-MS/MS analysis of A. creber extract allowed the characterization of five known fungal metabolites including: asperlactone, emodin, sterigmatocystin, deoxybrevianamide E, and norsolorinic acid. The highest antimicrobial activity was displayed against Candida albicans, with a mean strongest inhibition zone of 20.6 ± 0.8 mm, followed by Gram-positive drug-resistant bacteria. The MIC values of A. creber extract varied from 0.325 mg/ml to 5 mg/ml. A. creber extract was shown a potent antioxidant activity and a high level of phenolic compounds by recording 89.28% scavenging effect for DPPH free radical, 92.93% in ABTS assay, and 85.76 mg gallic acid equivalents/g extract in Folin-Ciocalteu assay. To our knowledge, this is the first study concerning biological and chemical activities of A. creber species. Based on the obtained results, A. creber could be a promising source of natural antimicrobial and antioxidant compounds

Auxin originated from Actinobacteria participates in abiotic stress mitigation and sustainable crop production

Plants activate their defence mechanisms to prevent damage caused by environmental stimuli through signaling pathways controlled by growth regulators. These stresses adversely affect plants' growth, disrupting the genetic control of cellular pathways and altering their metabolism, physiology and morphology. Auxin influences phenotypic plasticity under optimal and unfavourable growth conditions. This review discusses the progress in the research on auxin-mediated stress alleviation in response to abiotic stresses in plants. Then, a brief presentation of studies emphasizing the significance of auxin-producing actinobacteria and how microbial auxin promotes plant development and stress tolerance. Then, the review probes the importance of actinobacteria strains as auxin metabolic engineers and their use as natural auxin suppliers in agriculture. Finally, the review explores future biotechnology possibilities through small-scale, large-scale production and agriculture's gradual banishment of chemical phytosanitary inputs

Lignocellulosic biomass and industrial bioprocesses for the production of second generation bio-ethanol, does it have a future in Algeria?

info:eu-repo/semantics/publishe

Study of catalase production by an Aspergillus phoenicis mutant strain in date flour extract submerged cultures

The production of extracellular catalase in date flour submerged medium by a selected mutant Aspergillus phoenicis K30 (member of the Aspergillus niger group) was investigated. The strain was tested in 500 ml shake-flasks and in a 20 l bioreactor with date powder as a single carbon source. Extracellular catalase production reached 59 U ml-1 in both cases. This value is much greater than that of a wild-type strain (9.5 U ml-1). Microscopic examination showed that the extracellular catalase production was correlated with the ramified hyphals morphology in the external layer of the pellets

Screening of Candida boidinii from Chemlal spent olive characterized by higher alkaline-cold adapted lipase production

A total of 24 lipolytic yeasts were isolated from the spent olive derived from olive fruits of the Algerian variety Chemlal. One strain, G5, had the highest lipolytic activity (20 mm) on the tributyrin agar plate. The morphological, biochemical characterization and 18S rDNA gene analysis of the selected strain, confirms that it is Candida boidinii KF156789. The production of lipase and biomass were carried out in liquid and solid (spent olive) media. In submerged fermentation, it seemed that the production of enzyme reached its maximum 7.3 U/ml, whereas; the growth cells reached its maximum at 1.9 × 108 cell/ml. That can be explained by the assimilation of free fatty acids by this strain after degradation of olive oil by the enzyme. The production of lipase and biomass, in solid state fermentation, gave the maximum yield for cell growth (1.3 × 109 cell/ml), while lipolytic activity reached 4.8 U/g. The highest activity of the studied enzyme was at pH 7.0 and 37°C. The enzyme maintained more than 90% of its activity at pH 8.0-9.0 and 70% at temperature range of 4-40°C; it was concluded that the lipase from C. boidinii KF156789 has the potential to be an alkaline cold-adapted enzyme.Keywords: Candida boidinii KF156789, higher lipase, alkaline cold-adapted lipase, chemlal spent olive, solid state fermentation.African Journal of Biotechnology, Vol 13(11), 1287-129

Screening of spore-forming bacteria with probiotic potential in pristine algerian caves

The interest and exploration of biodiversity in subsurface ecosystems have increased significantly during the last 2 decades. The aim of this study was to investigate the in vitro probiotic properties of spore-forming bacteria isolated from deep caves. Two hundred fifty spore-forming microbes were enriched from sediment samples from 10 different pristine caves in Algeria at different depths. Isolates showing nonpathogenic profiles were screened for their potential to produce digestive enzymes (gliadinase and beta-galactosidase) in solid and liquid media, respectively. Different probiotic potentialities were studied, including (i) growth at 37°C, (ii) survival in simulated gastric juice, (iii) survival in simulated intestinal fluid, and (iv) antibiotic sensitivity and cell surface properties. The results showed that out of 250 isolates, 13 isolates demonstrated nonpathogenic character, probiotic potentialities, and ability to hydrolyze gliadin and lactose in solution. These findings suggest that a selection of cave microbes might serve as a source of interesting candidates for probiotics. IMPORTANCE Previous microbial studies of subsurface ecosystems like caves focused mainly on the natural biodiversity in these systems. So far, only a few studies focused on the biotechnological potential of microbes in these systems, focusing in particular on their antibacterial potential, antibiotic production, and, to some extent, enzymatic potential. This study explores whether subsurface ecosystems can serve as an alternative source for microbes relevant to probiotics. The research focused on the ability of cave microbes to degrade two substrates (lactose and gliadin) that cause common digestive disorders. Since these enzymes may prove to be useful in food processing and in reducing the effect of lactose and gliadin digestion within intolerant patients, isolation of microbes such as in this study may expand the possibilities of developing alternative strategies to deal with these intolerances

Kinetic models and parameters estimation study of biomass and ethanol production from inulin by Pichia caribbica (KC977491)

The growth kinetics and modeling of ethanol production from inulin by Pichia caribbica (KC977491) were studied in a batch system. Unstructured models were proposed using the logistic equation for growth, the Luedeking-Piret equation for ethanol production and modified Leudeking-Piret model for substrate consumption. Kinetic parameters (X0, μm, m, n, p and q) were determined by nonlinear regression, using Levenberg-Marquart method implemented in a Mathcad program. Since the production of ethanol was associated with P. caribbica cell growth, a good agreement between model predictions and experimental data was obtained. Indeed, significant R2 values of 0.91, 0.96, and 0.95 were observed for biomass, ethanol production and substrate consumption, respectively. Furthermore, analysis of variance (ANOVA) was also used to validate the proposed models. According to the obtained results, the predicted kinetic values and experimental data agreed well . Finally, it is possible to predict the development of P. caribbica using these models.Key words: Pichia caribbica, inulin, bioethanol, numerical simulation