25º Congresso Brasileiro de Microbiologia

SOYBEAN AND SUGAR CANE MOLASSES AND VINASSES AS BIOLOGICAL INDICATOR RECOVERY MEDIUM਀

Regina Elizabete Ferreira Dlugokenski (SESA-PR); Sandra Regina Barroso Ruíz Sella (SESA-PR); Belquis Palácio Guizelini (UFPR); Carlos Ricardo Soccol (UFPR); João Carlos Minozzo (SESA-PR)

The use of thermoresistant spores as biological indicators of the effectiveness of sterilization processes is essential for the safety of the health care service user. In order to achieve that, it proves necessary to confirm the destruction- or not- of the spores after sterilization cycle is finished. Second-generation (self-contained) biological indicators consist of a standardized suspension of spores in a cultivating medium capable of providing the necessary conditions for germinating and multiplying those spores that survived the sterilization process. Usually, synthetic and chemically defined culture media are used as developing medium. The present work aimed at replacing the traditionally used media by soybean vinasse, which is an agro-industrial residue resulting from processing soybean molasses to obtain alcohol. Standardized and thermoresistant spores of Geobacillus stearothermophilus ATCC 7953 are used for evaluating the germinative capacity of the medium after it had been exposed to moist heat (autoclavation). The methodology developed was the one recommended by the American Pharmacopoeia in its 29^th edition. The Biological Indicator- Esteriteste - produced by the Centro de Produção e Pesquisa de Imunobiológicos- CPPI, was used as standard, tha main component of which, in the formulation of the germinative medium, is the tripticasein soy broth (TSB), to which soluble starch (0,1g%), CaCl₂.2H₂O (0,018g%) and bromocresol purple (0,001g%) were added. The synthetic imported raw-material was replaced by soybean vinasse, in dilutions (V/V) of 1:25, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90 and 1:100, maintaining the other elements. The best results were observed from dilution 1:60 to 1:90, resulting in values of D_121^oC between 2,4 and 2,9 minutes. The addition of 0,8g% of yeast extract into the 1:70 dilution increased value of D_121^oC to 3,23 minutes. In all results, values equal to or above control were obtained. The analyses revealed that soybean vinasse has a great potential to be use as a medium for recovering spores damaged by heat in biologial indicators for steam sterilization. The use of agro-industrial waste in biotechnological processes aggregates the minimization of environmental impact caused by effluents and a decrease in production costs of the generated products.