Nowadays, the acidogenic fermentation process is an
interesting treatment option for wastewaters; however, it can
not compete economically with other industrial processes
about H2 or VFA production. Thus, some considerations
should be taken into account to increase the potential use of
this technology, such as:
Use of waste rich in carbohydrates, mainly glucose and
fructose.
Use of mixed culture, since the use of mixed culture
reduces the operational costs and present a better adaptive
capacity owing to microbial diversity, a better capacity to use
mixed substrates and the possibility of a continuous processing
[9].
An interesting waste rich in carbohydrates is the winery
wastewater. Winery industries play a significant role and
represent a considerable share of the Spanish economy,
mainly in the centre of Spain, such as the region of Castilla-La
Mancha, which produces about 18% of the European wine
production and about a 7.6% of the World wine production.
During the wine production, large quantities of effluents are
generated, mainly as a result of washing, rinsing and sanitising
operations [10].
The organic matter contained in winery wastewaters is
mainly soluble and easily biodegradable, and for these
reasons biological treatment processes are the best solution to
treat them. At the same time, these wastewaters present the
following characteristics [11]: High COD content and
a disproportionate carbon/nitrogen/phosphorus (which do
not recommend aerobic processes because of the high growth
yield and therefore nutrient requirements); seasonal production
(which recommends a process with a high maximum
specific growth rate) and high generation rate as well as
expensive management and storage (which recommends
a process with high specific activity). Moreover, winery
wastewaters contain glucose and fructose as main pollutants
[12], being that, the monosaccharides which produce the
highest amounts of hydrogen according to Jianzheng e