Optimization of dextran production from Leuconostoc strains isolated from different dairy products from Ouargla region Algeria

Leuconostoc (Ln) sp. belongs to a group of lactic acid bacteria, which has the capacity to produce dextran (an exopolysaccharides) in the presence of su-crose. dextran is industrially important, it was the first microbial exopolysac-charide affirmed for commercial use. This study aimed to optimize the pro-duction of the synthesized dextran by Ln strains species isolated from differ-ent dairy products. Morphological, cultural, physiological and biochemical characteristics were employed to identify 23 isolated strains. We have identi-fied the species: Ln. gelidum, Ln. carnosum, Ln. citreum, Ln. fallax, Ln. mesen-teroides subsp mesenteroides, Ln. mesenteroides subsp dextranicum, Ln. mesenteroides subsp cremoris. 20 strains had the capacity to produce dex-tran from sucrose. The precipitation and quantification of EPS on MRSs (Mark rogosa et sharpe sucrose) medium revealed a difference between the strains, by the total sugars assay method, the amount of EPS varied between 0.63 ± 0.19 and 2.41 ± 0.17 g / L of strains LnF70 and LnC1 (isolated from goat's milk), respectively. The dextran production from MRSs medium was better than from liquid MSE. The optimization of production on MRSs medi-um with different concentration of glucose, yeast extract and sucrose showed that the strains had good production with a concentration of 2% glucose, 0.3% yeast extract and 10% sucrose.

Luteapyrone, a Novel ƴ-Pyrone Isolated from the Filamentous Fungus Metapochonia lutea.

In the process of screening for new bioactive microbial metabolites we found a novel ƴ-pyrone derivative for which we propose the trivial name luteapyrone, in a recently described microscopic filamentous fungus, Metapochonia lutea BiMM-F96/DF4. The compound was isolated from the culture extract of the fungus grown on modified yeast extract sucrose medium by means of flash chromatography followed by preparative HPLC. The chemical structure was elucidated by NMR and LC-MS. The new compound was found to be non-cytotoxic against three mammalian cell lines (HEK 263, KB-3.1 and Caco-2). Similarly, no antimicrobial activity was observed in tested microorganisms (gram positive and negative bacteria, yeast and fungi).

Pollen viability and germination in Elaeis oleifera, Elaeis guineensis and their interspecific hybrid

ABSTRACT Elaeis oleifera chromosomes are similar to those of E. guineensis, with close gene pools for the production of interspecific O x G hybrids. The pollen viability and germination of E. oleifera ‘Coarí’ and E. guineensis ‘La Mé’ were compared to their interspecific hybrid O x G (‘Coarí’ x ‘La Mé’). The pollen viability was determined by the acetocarmine staining method (0.5 %) and the pollen germination by in vitro incubation on agar-sucrose medium (1.2-11.0 g in 100 mL of distilled water). The pollen viability and germination of the ‘Coarí’ x ‘La Mé’ hybrid were significantly lower than those of their parents. The percentage of pollen viability by acetocarmine staining was higher than that of in vitro germination, indicating that not all pollen grains classified as viable germinated on the agar-sucrose medium. The pollen germination test is a more reliable indicator than the staining viability test, because the latter only reveals that the pollen contains the enzymes necessary to initiate germination, while the germination test determines the emission and development of the pollen tube.

Isolasi dan Karakterisasi Bakteri Penghasil Etanol dari Lingkungan Industri Arak Bali di Desa Merita dan Tri Eka Buana, Karangasem-Bali

The purpose of this research is isolation and characterization to find potential bacteria which can produce the most optimal ethanol from the Arak Bali industry in Karangasem Regency, Bali. Bacteria were isolated by exposure method in open air using selective media Zymomonas Sucrose Medium (ZSMA) with the addition of nystatin as much as 0.18 g / L as an antifungal then samples were taken at three different points in one Arak Bali production location, namely the distillation place, the fermentation room for roomie, and the place of taking coconut juice under the coconut tree and the variation of time is 15, 30, and 60 minutes of exposure. Gas checking is done on the bacteria obtained to select its ability to produce ethanol. The results of the scanning of 11 best isolates using UV-visible spectrophotometry were fermented on 500 mL ZSM media for 10 days. BM1-CP14 is the best isolate to produce total ethanol of 15.33 mL through the fermentation process. The results of the characterization of BM1-CP14 isolates were Gram-positive bacteria in the form of bacilli, anaerobic and non-motile bacteria. The results showed that bacteria isolated from open-air also can produce ethanol. Keyword: ethanol, Arak Bali, airborne bacterial exposure, isolation, characterization, UV-Visible spectrophotometry

Isolation and identification of a strain producing riboflavin

Aim. Aim of investigation was to receive riboflavin strain-producers using natural sources for development of riboflavin technology. Methods. Strain-producers were isolated by the method of imprints (replica). The identification of stains was done by commonly used techniques using the «Bergey's Manual of Systematic Bacteriology». The resulting clones were tested for accumulation of riboflavin by fluorometric method. Results. 9 natural sources (seeds of corn and potato tubers) were investigated, pure cultures of microorganisms werr isolated and their identification was carried out. Two types of bacterial colonies of the genus Bacillus were identified. Selected strains weretested for antibiotic susceptibility and for the ability to accumulate riboflavin. Conclusions. As a result of the research, strain-producing riboflavin is isolated, the strain is classified as B. subtilis. The strain accumulated 4.3 g / l of riboflavin in a sucrose medium during a 72 hours cultivation. This strain was accepted as a source for the development of riboflavin technology. Keywords: riboflavin, stain, microbial synthesis, Bacillus subtilis.

Optimization for Oxalic Acid Production by Aspergillus niger Using Response Surface Methodology

Aims: To optimize selected process variables for oxalic acid production by Aspergillus niger using Response surface methodology. Study Design: Central composite design. Place and Duration of Study: Department of Microbiology, University of Port Harcourt, Rivers State, Nigeria. Methodology: Three media for the study was set up- algal biomass medium, sucrose medium and mixture of both algal biomass and sucrose medium. Inoculum of Aspergillus niger was prepared and subsequently inoculated into media for oxalate production by submerged fermentation. The oxalate produced after 14 days was determined by the catalytic effect of oxalic acid on the redox reaction between rhodamine B and dichromate. Results: The predicted conditions of pH 6.838, temperature 35ºC and substrate algal biomass and sucrose with oxalic acid production of 8.618 g/L were reported in the study. This slightly varies with the experimental conditions of pH 6, temperature 35ºC, algal biomass and sucrose mixture and oxalic yield of 12.12 g/L. The R2 value of 0.968 validates the model and adjusted R2 of 0.9449 shows that the model is significant. Conclusion: The study shows the feasibility of using the response surface methodology (RSM) in optimizing pH, temperature and substrate for the production of oxalic acid (g/l). It further shows the increased possibility of algal biomass as alternative feedstock for production of organics.

Sucrose ‘Versus’ Trehalose Cryoprotectant Modification in Oocyte Vitrification : A Study of Embryo Development

Numerous studies reported that vitrification, an ultra-rapid cooling technique, seems to be highly effective and could increase oocyte survival rate rather than slow freezing. The successful of oocyte vitrification depends on the proper combination of type and concentration of cryoprotectant. This study was addressed to determine the effects of the combination of type and concentration of cryoprotectants of vitrification media, notably in the embryo development. This experimental research was conducted by using oocyte obtained from thirty-two adult female Deutschland, Denken and Yoken (DDY) mice (7-8 weeks old). The MII mice oocytes were vitrified within 24 h after retrieval using the Cryotop method with cryoprotectants as follow : sucrose (16.5% EG, 16.5% DMSO, 0.5 mol/l sucrose), trehalose (16.5% EG, 16.5% DMSO, 0.5 mol/l trehalose) and Kitazato. The embryo development and morphological grading was observed at 2-cell and 8-cells under reverse phase light microscope and inverted microscope. This study demonstrated a good embryo development and morphological grading in sucrose and trehalose vitrification media. In embryo development, trehalose medium seems more superior compared to sucrose medium, even though Kitazato was the most superior compared to both. In the morphological grading, in 2-cells embryo, there were no significant differences between the three cryoprotectants, While, in 8-cells embryo, trehalose medium appeared to be superior compared to sucrose medium, even though seemed more inferior compared to Kitazato. The appropriate type and concentration of sugar as extracellular cryoprotectant was trehalose in oocyte vitrification based on embryo development, compared to sucrose.

Influence of chlorpromazine on the resistance of erythrocytes of rats of different ages to hypertonic conditions

The osmotic stability of native and modified with chlopromazine (CPR) erythrocytes of 1- and 12-month rats to hypertonic conditions in sucrose solutions and hypertonic shock (4.0 M NaCl) has been studied. It has been shown that 2-min incubation of rat erythrocytes of different ages in hypertonic sucrose media does not reveal any differences in the osmotic stability of these cells. In this case, CPR does not affect cell hemolysis. An increase of the incubation time in hypertonic sucrose solutions to 30 minutes allowed detecting a greater osmotic sensitivity of erythrocytes of 1-month animals to the action. In this case, the protective effect of CPR for older age rat erythrocytes (12 months) has been established. It has been found that in 4.0 M NaCl the hemolysis level of animal erythrocytes of both age groups increases with preliminary incubation (2 min) in a sucrose medium with a concentration of 0.7 M and above. With increasing exposure time (30 min) in sucrose hypertonic solutions, the sensibilization of animal erythrocytes of both age groups to the action of hypertonic shock is also intensified. In this study it has been shown that the influence of CPR on the sensitivity of 1-month-old animal erythrocytes to the transfer in 4.0 M NaCl depends on the tonicity and duration of the cell initial incubation in sucrose solutions. Thus, CPR increases the osmotic resistance of erythrocytes, which were preexposed in sucrose solutions at a concentration of 0.6–0.8 M for 2 and 30 min. Some increase of hemolysis level of these animals erythrocytes modified with CPR in 4.0 M NaCl has been observed after 2 min of incubation in sucrose solutions at a concentration of 0.27–0.5 M. The exclusively protective influence of CPR on 12-month-old animal erythrocytes in conditions of hypertonic shock has been revealed. A quantitative estimation of the efficiency of CPR at hypertonic shock (4.0 M NaCl) of different age animal erythrocytes has been carried out by calculation of the antihemolytic activity value (AG). Short-term incubation (2 min) in a sucrose media does not reveal any differences in the values of AG of CPR for erythrocytes of both age groups. For the cells of young rats, increase of AG of CPR is observed at incubation in sucrose medium to 30 min and for erythrocytes of the older group – to 10 min. With an increase in incubation time of up to 60 min the CPR efficiency in hypertonic saline media is reduced for rat cells in both age groups but in varying degrees.

Improving Conditions for Gliotoxin Production by Local Isolates of Aspergillus fumigatus

Thirty two isolates of Aspergillus fumigatus were obtained from a total of 44 samples of sputum, nose swab and tracheal aspirate from suspected patient with aspergillosis were also collected from February 2014 to June 2014. A morphological examination of A. fumigatus was first made with naked eye and at low magnification power of microscope after that detailed examination was done by measuring the dimensions of the microscopic structures, photographing the microscopic structures and using relevant literature. Results appeared conical-shaped terminal vesicles, uniseriate row of phialides on the upper two thirds of the vesicle, conidiophore stipes were short, phialides arrange uniseriate upper vesicle conidia and parallel to axis of conidiophore, produced in chains of spore basipetally from phialides, the chains of spore were borne directly in the absence of metulae and represented by septet and branching hyphae. The ability of A. fumigatus for GT production was investigated using thin layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC) techniques and results showed that GT was produced by 81.25% of A. fumigatus isolates. Optimum conditions for GT production by A. fumigatus 16 (AF-16) isolate were determined by submerged fermentation using Yeast extract sucrose medium. Results indicated that AF-16 isolate was the highest GT producer on Yeast Exract Sucrose medium with inoculum size 2×107 conidium and incubation at 32ºC for 15 days and the concentration of gliotoxin was (4511µg mL-1).

Mutation of AN39-1 for production and characterization of constitutive, thermostable and pH-resistant dextransucrase / Konstitutif, sıcaklığa ve pH’ya dayanıklı dekstransukrazların üretimi ve karakterizasyonu için AN39-1’in mutasyonu

Objective: Leuconostoc mesenteroides AN39-1 has recently been isolated from Crataegus orientalis var. Orientalis. It produces inducible extracellular dextransucrase (EC 2.4.1.5) forming dextran from sucrose. The aim of this study was (1) to obtain constitutive, pH-resistant and thermostable dextransucrase, (2) to characterization of these dextransucrase.Methods: Mutagenesis was carried out on the parent strain (AN39-1) using UV, ethyl methane sulfonate, and N- methyl- N´-nitro-N-nitrosoguanidine. Dextransucrases from wild type (AN39-1) and the mutant strain (A26-2/11) were purified by polyethylene glycol (PEG) precipitation and characterized.Results: Mutants (A26, A26-2, and A26-2/11) hyper producing and constitutive for dextransucrase were isolated. The mutants (A26, A26-2, A26-2/11) produced 7.2, 8.1, and 2.0 times more dextransucrase activity as compared to parent strain on sucrose medium, respectively. In addition, the mutants produced dextransucrase on glucose medium with higher activities (3.0-5.8 times) than what the parental strain produced on sucrose medium. The mutant enzyme (A26-2/11) was much more thermostable than the native enzyme and resistant to pH more than dextransucrase of AN39-1. The dextransucrase from mutant strain was stable up to 35°C and pH of 7.5 for 3 hr.Conclusion: The structures of dextrans produced by wild type and mutant enzymes were similar to commercially produced B-512 F dextran. Thus, the newly dextransucrases produced by mutant strain could find industrial applications at higher temperature and pH.