Utilization of a factorial design to study the composting of hydrolyzed grape marc and vinification lees.
Hydrolyzed grape marc (HGM) is the solid residue generated after the acid hydrolysis of grape marc to obtain hemicellulosic sugars for biotechnological purposes. In this work, HGM containing cellulose and lignin was composted together with vinification lees to obtain plant substrates on a laboratory scale. The effects of temperature (in the range of 20-50 degrees C), concentration of vinification lees (5-100 g/100 g of hydrolyzed grape marc), and concentration of CaCO(3) on the final properties of the composted HGM were studied by means of an experimental plan with factorial structure. The interrelationship between dependent and operational variables was established by models including linear, interaction, and quadratic terms. The most influential variable on the C/N ratio and P, K and Mg contents of composted substrates was the vinification lees concentration followed by the temperature, whereas on Na content and electrical conductivity the most influential variable was the temperature followed by the vinification lees concentration. The results of the incubation experiments indicated that optimal conditions for obtaining plant substrates can be achieved by composting 1:1 mixtures of hydrolyzed grape marc and vinification lees, in the presence of 5 g of CaCO(3)/100 g of HGM. During composting the pH of the mixtures increased from 5.1-6.7 to 7.1-8.1, salinity and water-soluble carbon were reduced in most cases, and the initial phytotoxicity disappeared in all of the mixtures tested.
Departamento de Edafoloxia e Quimica Agricola, Facultade de Farmacia, Universidade de Santiago de Compostela, Santiago de Compostela, Spain. remigio.paradelo@usc.es
Remigio
R
Paradelo
Ana B
AB
Moldes
María T
MT
Barral
D001709:Biotechnology; D006863:Hydrogen-Ion Concentration; D012987:Soil; D013696:Temperature; D027843:Vitis
D012987:Soil