Recovery and purification of acetic acid from extremely diluted solutions using a mixed bed ion exchange resin - technical feasibility.

A downstream process for the recovery and purification of acetic acid (AA) from an extremely diluted solution (100 mg L) also containing a mixture of contaminating inorganic salts in the form of bicarbonates, phosphates, sulfates and chlorides (DPM medium) has been developed, showing its technical feasibility. The process involves two successive steps based on the use of a mixed bed ion exchange (IEX) resin. The first step, a demineralization treatment to remove the inorganic anions that could potentially interfere with the recovery and purification of AA, involves a combined treatment of calcium precipitation, acidification with the Amberlite IR-120 resin and treatment with the Amberlite MB20 mixed bed resin.

Two-step oxidation of glycerol to glyceric acid catalyzed by the Phanerochaete chrysosporium glyoxal oxidase.

Glyoxal oxidase of P. chrysosporium is a radical copper oxidase that catalyzes oxidation of aldehydes to carboxylic acids coupled to dioxygen reduction to H(2)O(2). In addition to known substrates, glycerol is also found to be a substrate for glyoxal oxidase.

High yield production of monomer-free chitosan oligosaccharides by pepsin catalyzed hydrolysis of a high deacetylation degree chitosan.

The high molecular weight of chitosan, which results in a poor solubility at neutral pH values and high viscosity aqueous solutions, limits its potential uses in the fields of food, health and agriculture. However, most of these limitations are overcome by chitosan oligosaccharides obtained by enzymatic hydrolysis of the polymer. Several commercial enzymes with different original specificities were assayed for their ability to hydrolyze a 93% deacetylation degree chitosan and compared with a chitosanase.

Conidiation induction in Penicillium.

Asexual spores or conidia are dispersive propagules produced as an alternative to vegetative growth by a diverse group of filamentous fungi. The cellular development programmes which govern conidiation have been intensely studied in the last few decades, although important gaps stand in the way of our understanding of this phenomenon, namely in the areas of the environmental sensing mechanisms and signal transduction pathways. The aim of this review is to summarize the current advances in conidiation induction in the genus Penicillium, and to put them into context with the state of our knowledge stemming from work in widely studied fungal model systems.

Conidiation in Penicillium cyclopium is induced by conidiogenone, an endogenous diterpene.

The filamentous fungus Penicillium cyclopium conidiates in the presence of calcium ions in submerged culture without nutrient limitation according to a precisely timed program. Conidiation could be prematurely induced in a nutritionally sufficient medium which had previously supported growth, suggesting that a metabolite which influenced the process was produced. A diterpenoid with conidiation-inducing activity, conidiogenone, was purified from the culture medium, along with conidiogenol, a putative derivative with delayed activity.