Gellan gum production was carried out by Sphingomonas paucimobilis ATCC 31461 in a simplified medium with a short incubation time, and a kinetic model for understanding, controlling, and optimizing the fermentation process was proposed. The results revealed that glucose was the best carbon source and that the optimal concentration was 30 g liter(-1). As for the fermenting parameters, considerab...

In general, it is accepted that the production of bacteriocins in lactic acid bacteria cultures implies moderately to highly restrictive conditions regarding the availability of oxygen. However, the situation appears to be more complex, probably owing to the facultative anaerobic character of these microorganisms. By studying the culture of eight strains of lactic acid bacteria carried out in v...

We study the evolution of homogeneous and isotropic, flat cosmological models within the general scalar-tensor theory of gravity with arbitrary coupling function and potential and scrutinize its limit to general relativity. Using the methods of dynamical systems for the decoupled equation of the Jordan frame scalar field we find the fixed points of flows in two cases: potential domination and m...

We introduce the notion of quasi-Feistel network, which is generalization of the Feistel network, and contains the Lai-Massey scheme as an instance. We show that some of the works on the Feistel network, including the works of Luby-Rackoff, Patarin, Naor-Reingold and Piret, can be naturally extended to our setting. This gives a new proof for theorems of Vaudenay on the security of the Lai-Masse...

The asymptotic Elias upper bound of codes designed for Hamming distance is well known. Piret [3] and Ericsson [4] have extended this bound for codes over symmetric PSK signal sets with Euclidean distance and for codes over signal sets that form a group, with a general distance function respectively. The tightness of these bounds depend on a choice of a probability distribution, and finding the ...

In a distributed clustering algorithm introduced by Coffman, Courtois, Gilbert and Piret [1], each vertex of Z receives an initial amount of a resource, and, at each iteration, transfers all of its resource to the neighboring vertex which currently holds the maximum amount of resource. In [4] it was shown that, if the distribution of the initial quantities of resource is invariant under lattice...

The present study focuses on effects of initial pH on dibenzothiophene (DBT) desulfurization via 4S pathway by growing cells of Ralstonia eutropha. For so doing, temporal changes of biomass concentration, glucose as a sole carbon source, pH value, and 2-hydroxybiphenyl (2-HBP) formation have been monitored during the bioprocess. The biomass concentration has been modeled by the logistic equatio...

The present study focuses on effects of initial pH on dibenzothiophene (DBT) desulfurization via 4S pathway by growing cells of Ralstonia eutropha. For so doing, temporal changes of biomass concentration, glucose as a sole carbon source, pH value, and 2-hydroxybiphenyl (2-HBP) formation have been monitored during the bioprocess. The biomass concentration has been modeled by the logistic equatio...