Differential evolution (DE) is arguably one of the most powerful stochastic real-parameter optimization algorithms in current use. DE operates through similar computational steps as employed by a standard evolutionary algorithm (EA). However, unlike traditional EAs, the DE-variants perturb the current-generation population members with the scaled differences of randomly selected and distinct population members. Therefore, no separate probability distribution has to be used for generating the offspring. Since its inception in 1995, DE has drawn the attention of many researchers all over the world resulting in a lot of variants of the basic algorithm with improved performance. This paper presents a detailed review of the basic concepts of DE and a survey of its major variants, its application to multiobjective, constrained, large scale, and uncertain optimization problems, and the theoretical studies conducted on DE so far. Also, it provides an overview of the significant engineering applications that have benefited from the powerful nature of DE.

/pdf/differential-evolution-a-survey-of-the-state-of-the-art-3lz840pz2t.pdf

Differential Evolution: A Survey of the State-of-the-Art

An overview of the self-organizing map algorithm, on which the papers in this issue are based, is presented in this article.

The Self-Organizing Map

Extraction of extracellular polymers from activated sludge using a cation exchange resin

Bioconversion of lignocellulose by microbial fermentation is typically preceded by an acidic thermochemical pretreatment step designed to facilitate enzymatic hydrolysis of cellulose. Substances formed during the pretreatment of the lignocellulosic feedstock inhibit enzymatic hydrolysis as well as microbial fermentation steps. This review focuses on inhibitors from lignocellulosic feedstocks and how conditioning of slurries and hydrolysates can be used to alleviate inhibition problems. Novel developments in the area include chemical in-situ detoxification by using reducing agents, and methods that improve the performance of both enzymatic and microbial biocatalysts.

/pdf/bioconversion-of-lignocellulose-inhibitors-and-2fj6w3tbs6.pdf

Bioconversion of lignocellulose: inhibitors and detoxification

http://sgpwe.izt.uam.mx/files/users/uami/acym/Enterococos_en_alimentos_y_salud-2006.pdf

The role and application of enterococci in food and health.

Identification of target genes conferring ethanol stress tolerance to Saccharomyces cerevisiae based on DNA microarray data analysis.

To investigate the effects of lactate on cell growth and antibody production, a new method of maintaining the lactate concentration constant in a fed-batch culture is described. When the pH was initially adjusted by sodium hydroxide, the specific growth rate decreased and specific death rate increased with an increase of lactate concentration. To investigate whether the inhibition was due to the lactate concentration itself or to the osmotic pressure, the effect of the osmotic pressure adjusted by sodium chloride was compared with that of sodium lactate. When the osmotic pressure was adjusted to same condition as that of sodium lactate using sodium chloride, the specific growth data showed the same degree of growth inhibition. It was thus evident that the inhibition to cell growth was mainly due to osmotic pressure while lactate production from glucose was found to be inhibited by the lactate itself compared with sodium chloride. The specific antibody production rate had a maximum value within a certain range of lactate concentration. Moreover, specific antibody production rate had a unified relationship with the kinetic parameter mu, in spite of the different causes of inhibition by lithium lactate and sodium lactate. A certain "trade-off" relationship between growth and antibody production existed at higher growth rates.

Suteaki Shioya

Papers

Identification of target genes conferring ethanol stress tolerance to Saccharomyces cerevisiae based on DNA microarray data analysis.

Effects of lactate concentration on hybridoma culture in lactate-controlled fed-batch operation.

Biological detoxification of waste house wood hydrolysate using Ureibacillus thermosphaericus for bioethanol production

Beer Volatile Compounds and Their Application to Low-Malt Beer Fermentation

Enhanced kefiran production by mixed culture of Lactobacillus kefiranofaciens and Saccharomyces cerevisiae.