Multiple linear regression models to simulate spore yields of Bacillus amyloliquefaciens BS13 through optimization of medium composition.

Bacillus amyloliquefaciens is a food spoilage spore-forming bacterium. Its spores are useful for multiple biotechnological applications. Nevertheless, few reports are available regarding the achievement of a high cell density and good sporulation effectiveness under fermentation conditions.

Production of freeze-dried yeast culture for the brewing of traditional sorghum beer, tchapalo.

Freeze-drying is a well-known dehydration method widely used to preserve microorganisms. In order to produce freeze-dried yeast starter culture for the brewing purpose of African sorghum beer, we tested protective agents (sucrose, glucose, glycerol) in combination with support materials (millet, maize, sorghum, and cassava flours) at 1:1 ratio (v/v). The yeast strains Saccharomyces cerevisiae F 12-7 and Candida tropicalis C 0-7 previously isolated from sorghum beer were used in a mixed culture at a ratio of 2:1 (C.

Fermentation profile of Saccharomyces cerevisiae and Candida tropicalis as starter cultures on barley malt medium.

Saccharomyces cerevisiae C8-5 and Candida tropicalis F0-5 isolated from traditional sorghum beer were tested for kinetic parameters on barley malt extract, YPD (863 medium) and for alcohol production. The results showed that C. tropicalis has the highest maximum growth rate and the lowest doubling time.

Biocontrol and Plant Growth Promotion Characterization of Bacillus Species Isolated from Calendula officinalis Rhizosphere.

The phenotypic and genotypic diversity of the plant growth promoting Bacillus genus have been widely investigated in the rhizosphere of various agricultural crops. However, to our knowledge this is the first report on the Bacillus species isolated from the rhizosphere of Calendula officinalis. 15 % of the isolated bacteria were screened for their important antifungal activity against Fusarium oxysporum, Botrytis cinerea, Aspergillus niger, Cladosporium cucumerinium and Alternaria alternata.

Characterization of amylolysin, a novel lantibiotic from Bacillus amyloliquefaciens GA1.

Background: Lantibiotics are heat-stable peptides characterized by the presence of thioether amino acid lanthionine and methyllanthionine. They are capable to inhibit the growth of Gram-positive bacteria, including Listeria monocytogenes, Staphylococcus aureus or Bacillus cereus, the causative agents of food-borne diseases or nosocomial infections. Lantibiotic biosynthetic machinery is encoded by gene cluster composed by a structural gene that codes for a pre-lantibiotic peptide and other genes involved in pre-lantibiotic modifications, regulation, export and immunity.

Improving effect of metal and oxide nanoparticles encapsulated in porous silica on fermentative biohydrogen production by Clostridium butyricum.

This paper investigated the enhancement effect of nanometre-sized metallic (Pd, Ag and Cu) or metallic oxide (FexOy) nanoparticles on fermentative hydrogen production from glucose by a Clostridium butyricum strain. These nanoparticles (NP) of about 2-3 nm were encapsulated in porous silica (SiO2) and were added at very low concentration (10(-6) mol L(-1)) in batch hydrogen production test. The cultures containing iron oxide NP produced 38% more hydrogen with a higher maximum H2 production rate (HPR) of 58% than those without NP or with silica particles only.

Placenta-like structure of the aphid endoparasitic wasp Aphidius ervi: a strategy of optimal resources acquisition.

Aphidius ervi (Hymenoptera: Braconidae) is an entomophagous parasitoid known to be an effective parasitoid of several aphid species of economic importance. A reduction of its production cost during mass rearing for inundative release is needed to improve its use in biological control of pests. In these contexts, a careful analysis of its entire development phases within its host is needed.

The use of Macronet resins to recover gamma-decalactone produced by Rhodotorula aurantiaca from the culture broth.

During the biotransformation of castor oil into gamma-decalactone, R. aurantiaca produced both the lactone form and its precursor (4-hydroxydecanoic acid). After six days of culture, a maximum yield of gamma-decalactone of 6.

Use of a nisin-producing starter culture of Lactococcus lactis subsp, lactis to improve traditional fish fermentation in Senegal.

Lactococcus lactis subsp. lactis strain CWBI B1410, which produces various antibacterial compounds including organic acids and nisin, was used as a starter culture to improve the traditional Senegalese fish fermentation in which fish are mostly transformed to guedj by spontaneous fermentation for 24 to 48 h at ambient temperatures near 30 degrees C followed by salting (with NaCl) and sun drying. Assays were performed on lean fish (Podamasys jubelini) and fat fish (Arius heudelotii) purchased at a local market.

The utilization of gum tragacanth to improve the growth of Rhodotorula aurantiaca and the production of gamma-decalactone in large scale.

The production of gamma-decalactone and 4-hydroxydecanoic acid by the psychrophilic yeast R. aurantiaca was studied. The effect of both compounds on the growth of R.

Ecological fitness of Bacillus subtilis BGS3 regarding production of the surfactin lipopeptide in the rhizosphere.

Cyclic lipopeptides and particularly surfactins produced by Bacillus species retain antibacterial, antiviral, biofilm-forming and plant resistance-inducing activities. In most cases, their role in biological control of plant diseases was evoked on the basis of in vitro assays or by using non-producing/overproducing mutants but there is a need for more direct evidence of an efficient lipopeptide biosynthesis in the rhizosphere. In this work, we coupled LC-MS quantification of the lipopeptides secreted by cells colonizing tomato plants with the use of psrfA-lacZ reporter system integrated within the BGS3 chromosome to study the expression of the surfactin operon in planta.

Insights into the defense-related events occurring in plant cells following perception of surfactin-type lipopeptide from Bacillus subtilis.

Multiple strains of Bacillus subtilis were demonstrated to stimulate plant defense responses, and cyclic lipopeptides may be involved in the elicitation of this induced systemic resistance phenomenon. Here, we further investigated molecular events underlying the interaction between such lipopeptides and plant cells. Addition of surfactin but not fengycin or iturin in the micromolar range to tobacco cell suspensions induced defense-related early events such as extracellular medium alkalinization coupled with ion fluxes and reactive oxygen species production.

Study on mass transfer of isopropylbenzene and oxygen in a two-phase partitioning bioreactor in the presence of silicone oil.

A two-phase partitioning bioreactor to treat gas effluents polluted by volatile organic compound has been developed. In this work, both the mass transfer of isopropylbenzene (IPB) and oxygen have been considered in relation to their influence on the hydrodynamics of the reactor and the type of silicone oils used as a second phase. The synergistic effect of silicone oil and stirrer speed on the global oxygen mass transfer coefficient (KLa) and gas holdup (up to 12%) have been investigated.

Xylanase production by Penicillium canescens on soya oil cake in solid-state fermentation.

There is an increasing interest for the organic residues from various sectors of agriculture and industries over the past few decades. Their application in the field of fermentation technology has resulted in the production of bulk chemicals and value-added products such as amino acid, enzymes, mushroom, organic acids, single-cell protein, biologically active secondary metabolites, etc. (Ramachandran et al.

Improvement of Yarrowia lipolytica lipase production by fed-batch fermentation.

Two different types of fed-batch fermentation were investigated to improve production yields of the Lip2 extracellular lipase in Y. lipolytica mutant-strain LgX64.81 grown in a 20l bioreactor.

Production of gamma-decalactone by a psychrophilic and a mesophilic strain of the yeast Rhodotorula aurantiaca.

Among 18 psychrophilic strains isolated near the Antarctic Station, the psychrophilic strain Rhodotorula aurantiaca A19 was selected for its ability of growth and gamma-decalactone production at low temperatures. The effects of temperature, initial pH, and castor oil concentration on the growth and gamma-decalactone production by a psychrophilic and a mesophilic strain of R. aurantiaca were investigated.

Improvement of oxygen transfer coefficient during Penicillium canescens culture. Influence of turbine design, agitation speed, and air flow rate on xylanase production.

To improve xylanase productivity from Penicillium canescens 10-10c culture, an optimization of oxygen supply is required. Because the strain is sensitive to shear forces, leading to lower xylanase productivity as to morphological alteration, vigorous mixing is not desired. The influence of turbine design, agitation speed, and air flow rate on K1a (global mass transfer coefficient, h(-1)) and enzyme production is discussed.

Improvement of lactic cell production.

The production of Lactobacillus brevis has been improved by changing the medium composition and the physiological conditions. The cellular concentration reaches 8.2 x 10(10) cells/mL in 21 h with a fed-batch technique in MRS medium.

Effect of monopropylene glycol and gamma irradiation on Yarrowia lipolytica lipase stabilization.

This work investigated the effects of monopropylene glycol, protease inhibitor, and gamma irradiation on Yarrowia lipolytica lipase stability during storage. Enzyme liquid stabilization was achieved by addition of monopropylene glycol (MPG) at respective concentrations of 50, 75, and 90%, the protease inhibitors (P2714 and P8215) at 0.1%, and the gamma irradiation with 10kGy, 15kGy, and 25kGy doses.

Investigation of the effect of different extracellular factors on the lipase production by Yarrowia lipolityca on the basis of a scale-down approach.

The influence of three extracellular factors (namely, the methyl oleate dispersion in the broth, the dissolved oxygen variations, and the pH fluctuation) on the lipase production by Y. lipolytica in batch bioreactor has been investigated in different scale-down apparatus. These systems allow to reproduce the hydrodynamic phenomena encountered in large-scale equipments for the three specified factors.

Survival of freeze-dried leuconostoc mesenteroides and Lactobacillus plantarum related to their cellular fatty acids composition during storage.

Lactic acid bacteria strains Lactobacillus plantarum CWBI-B534 and Leuconostoc ssp. mesenteroïdes (L. mesenteroïdes) Kenya MRog2 were produced in bioreactor, concentrated, with or without cryoprotectants.

Comparison of Yarrowia lipolytica lipase immobilization yield of entrapment, adsorption, and covalent bond techniques.

The purpose of this study was to immobilize lipase from Yarrowia lipolytica using three methods including inclusion, adsorption, and covalent bond to study enzyme leaching, storage, and catalytic properties. Sodium alginate and chitosan were the polymers selected to immobilize lipase by inclusion. The beads of each polymer were dried by freeze drying and fluidization.

Survival rate analysis of freeze-dried lactic acid bacteria using the arrhenius and z-value models.

The survival rate of five freeze-dried bacteria species, Lactobacillus plantarum, Lactobacillus pentosus, Weisella paramesenteroides, Leuconostoc mesenteroides, and Lactobacillus fermentum, was described in terms of reaction rate constants (D or k) and temperature sensitivity of rate constants (z or Ea). The freeze-dried strains were stored under vacuum at 55, 37, and 4 degrees C for 168 h, 17 days, and 2 months, respectively. D-values decreased and k increased with an increase of the storage temperature.

Acetobacter senegalensis sp. nov., a thermotolerant acetic acid bacterium isolated in Senegal (sub-Saharan Africa) from mango fruit (Mangifera indica L.).

A thermotolerant acetic acid bacterium, designated strain CWBI-B418(T), isolated in Senegal from mango fruit (Mangifera indica), was characterized in detail by means of genotypic and phenotypic methods. The novel strain was strictly aerobic and exhibited optimal growth on YGM medium at 35 degrees C. Cells were Gram-negative, motile and coccoid.

Amino acids, iron, and growth rate as key factors influencing production of the Pseudomonas putida BTP1 benzylamine derivative involved in systemic resistance induction in different plants.

The biological control bacterium Pseudomonas putida BTP1 exerts its protective effect mostly by inducing an enhanced state of resistance in the host plant against pathogen attack [induced systemic resistance (ISR)]. We previously reported that a specific compound derived from benzylamine may be involved in the elicitation of the ISR phenomenon by this Pseudomonas strain. In this article, we provide further information about the N,N-dimethyl-N-tetradecyl-N-benzylammonium structure of this determinant for ISR and show that the benzylamine moiety may be important for perception of the molecule by root cells of different plant species.