Fulvia Chiampo

Production of polyhydroxyalcanoates (PHAs) using milk whey and dairy wastewater activated sludge: Production of bioplastics using dairy residues

The production of polyhydroxyalcanoates (PHAs), which are biodegradable plastics, was studied using milk whey and dairy wastewater activated sludge to define a suitable C/N ratio, the pre-treatments required to reduce the protein content, and the effect of pH correction. The results show good production of PHAs at a C/N=50 and without pH correction. The use of dairy wastewater activated sludge has the advantage of not requiring aseptic conditions.

Influence of mixing on the particle size distribution of an organic precipitate

The influence of agitation and micromixing of reactants in the course of a semibatch precipitation has been investigated: in order to obtain a narrow particle size distribution (PSD) suitable for a quick filtration of solid, the influence of the mode of introduction of the precipitant as well as the impeller revolution speed has been studied. Small effects on PSD have been obtained acting on the impeller speed or the feed introduction point; on the other hand, when the precipitant and the solution are mixed in a TEE a strong effect on PSD is evident. The experimental work is the result of a co-operation between the Politecnico di Torino and the Dow Chemical Lepetit factory of Garessio (CN) Italy: it reproduces an industrial process and hence, due to industrial secrecy, details not relevant to the aim of the research will be omitted.

Multiphase catalytic kinetics in a three phase recirculating reactor

Abstract The kinetics of hydrogenation of a α-methylstyrene to cumene is studied in a multiphase recirculating reactor where the adsorption zone (gas-liquid) is separated from the reaction zone (liquid with dissolved hydrogen-catalyst). The reactor operated in a batch mode in respect of the product. A model of the reactor is presented, in which the accumulation of the product inside the catalyst pellet is considered: the model is able to define the operative conditions at which this accumulation, if not carefully taken into account, may affect the findings of the conversion rates. The experimental data confirm the model predictions.

Production of PHA from whey by indigenous microflora and activated sludge: preliminary investigation

Milk whey was employed to produce polyhydroxyalcanoates (PHA), using as inoculum either whey indigenous microflora or enriched activated sludge deriving from a dairy wastewater treatment plant. The aim of the present study was to test the capability of mixed consortia to produce PHA directly from lactose. The experimental runs demonstrated that milk whey lactose can constitute a cheap carbon source to synthesize PHA in fermentations where the microorganisms are represented by indigenous microorganisms or enriched activated sludge: this result constitutes an evident advantage since whey pre-treatment and aseptic conditions are not required. Tests with commercial whey powder (Molkolac®) and on raw milk whey showed a PHA production around 10 % (by weight on dry biomass).