D. Colombi, N. Verdoodt, C.R. Basso, B.F. Rossi and V.A. Pedrosa
Research and Development, Genotyping, Botucatu, Brazil
Brazil is one of the largest alcohol producers in the world, producing 26 billion liters by year. Studies have shown that yield loss in the fermentation of 10 to 15% are due to microbial contamination. Methods used today to evaluate microbial contamination depend on microscopic counting and plating techniques. These methods couldn't identity the contaminating organism and have high response time (one to five days), respectively.
Our solution to reduce industry loss is to develop a rapid kit (minutes), so alcohol industry will be able to have more timely interventions to stop or control contamination.
Biosensors based on gold nanoparticles can be bio conjugated with various ligands such as nucleic acids and antibodies. After the bio conjugation, they start forming aggregates, which shifts the absorption band to ca. 600-800 nm. This change can be observed by the naked eye or measured quantitatively with an ultraviolet-visible spectrophotometer.
Here we present a cheap and simple colorimetric method for detection of Lactobacillus sp. and Staphylococcus aureus using gold nanoparticles modified with antibody to produce an immunosensor. This detection system had a detection limit of 102 cfu/mL for both Lactobacillus Sp and Staphylococcus aureus in less than 10 minutes.
Keywords: Alcohol fermentation, bacteria contamination, nanoparticle.