Abstract

MATUTE-ALMEIDA, L.; GALINDO-SANDOVAL, Y.  and  DELAHAIS, I.. Evaluation of discard products of a soft drinks industry to be used as fermentable substrate by Saccharomyces cerevisiae. Nova scientia [online]. 2017, vol.9, n.18, pp.1-20. ISSN 2007-0705.  https://doi.org/10.21640/ns.v9i18.666.

Waste products from the industry of soft drinks were evaluated to be used as fermentation substrate by Saccharomyces cerevisiae, because these residues have between 5.5 to 13% of sugars. Under a completely randomized design with factorial arrangement 23, was studied the kinetics of growth of S. cerevisiae using a sterile environment based soft drinks discarded (black cola (P) with 12% sugar, caffeine, phosphoric acid and carbonated water or an isotonic drink (G) with 7% sugar, citric acid and salts), whose pH values ​​were adjusted to 4 or 4.5. The media were inoculated with a concentration of 10 g/L commercial yeast, incubated at 30 ° C with constant shaking of 100 rpm or 130 rpm. Samples were taken every 2 h, from inoculation to final fermentation time (12 h), were measured the soluble solid content, the ethanol concentration and the biomass production. Statistical analysis showed that the incubation time and substrate influenced the biomass production (p<0.01). The major production of biomass under the study conditions, was obtained when the initial pH was adjusted to 4.5 and was used 130 rpm as stirring speed for both substrates. Being obtained 15.4 g/L of biomass at 8 h of incubation in the substrate P (p<0.05) and 12.8 g/L of biomass in the substrate G. Also, the color removal drinks and 10% decrease in COD values was achieved. Based on these results it can be stated that it is possible to use non-alcoholic discard beverages as fermentable substrate in processes where it is inoculated, Saccharomyces cerevisiae.

Keywords : biomass; growth; soluble solids; submerged fermentation.