Ignacio de Ory

Optimization of immobilization conditions for vinegar production. Siran, wood chips and polyurethane foam as carriers for Acetobacter aceti

Abstract A complete experimental design has been developed to study the properties of three different solid carriers (Siran, wood chips and polyurethane foam) in the immobilization of acetic acid bacteria. Temperature-controlled reactors of 450-ml volume were employed to compare a standard immobilization procedure consisting of consecutive discontinuous acetic acid fermentations in the presence of the carrier. On reaching the final saturation condition, the different immobilized carriers were removed and introduced into identical sterilized reactors. These were then submitted to several semi-continuous fermentation cycles with the aim of characterising and comparing their acetification properties. Immobilization and acetification data obtained in this study have been evaluated in order to determine the best carrier material on the basis of several technical criteria. Polyurethane foam was the most successful because it allows a huge number of immobilized cells in the shortest time and leads to the highest acetification rate of the three assayed carriers.

Optimum starting-up protocol of a pilot plant scale acetifier for vinegar production

In the present work, the influences of ethanol (fermentation substrate) and acetic acid (fermentation product) concentrations on the starting-up of a pilot plant acetifier are evaluated. Some effects of activation and inhibition acting on bacterial growth of acetic acid bacteria are registered as a function of the concentrations of substrate and product. As a consequence of the related studies, an optimum starting-up protocol has been proposed. In this, the volumes of wine and inoculum that must be added at the beginning of the process, together with the appropriate instant to make the additions of fresh wine, are established. This protocol is perfectly scalable to other industrial acetifiers, following the proposed stages and addition sequences.

Xylanase production by Aspergillus awamori under solid state fermentation conditions on tomato pomace

Inthiswork,� tomatopomace,� awasteabundantlyava ilableintheMediterraneanandothertemperate� climatesagrofoodindustries,�hasbeenusedasraw �materialfortheproductionofsomehydrolyticenz ymes,� includingxylanase,�exopolygalacturonase�(exoPG), �cellulase�(CMCase)�and�α�amylase.�Theprincipalst ep� oftheprocessisthesolidstatefermentation�(SSF )�ofthisresiduebyAspergillus awamori.�Inseveral� laboratoryexperiments,�maximumxylanaseandexoPG �activitiesweremeasuredduringthefirstdaysof�

Operation in semi-continuous with a closed pilot plant scale acetifier for vinegar production

Abstract Several semi-continuous series of acetic acid fermentations were carried out in a novel pilot plant reactor (225 l) including a gas recycling system for the recovery of volatile compounds. The behaviour of substrate and product concentrations, acetification rates, stoichometric yields and oxygen consumption were analysed. Operation with this novel reactor proved some technical advantages in order to produce high quality vinegars: stoichometric yields of 100% and minimum oxygen supply.

Immobilization of Cells on Polyurethane Foam

In this chapter, protocols and details for the immobilization of a model cell onto polyurethane foam carriers are provided in order to facilitate the use of such systems in laboratory or industrial reactors. Polyurethane foam has recently acquired great relevance as a carrier for its good mechanical properties, high porosity, and large adsorption surface. In addition, it has a very low commercial cost. Two different immobilization protocols have been described, differing in the flow regime or the possibilities for the reactor: immobilization in a stirred tank reactor working in a discontinuous regime (by cycles) and immobilization in a packed column working in continuous operation mode. Protocols for carrier sterilization, analytical methodology, and immobilization are described.