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Beer is recognized as a safe beverage, owing to its excellent microbiological stability provided by its components, especially iso-α-acids from hop and ethanol which have antimicrobial activity. Despite these unfavourable conditions for bacteria, some lactic acid bacteria (LAB) can cause beer spoilage. Resistance to hop compounds is caused, in part, by the product of genes like horA. Understanding how LAB adapts to hop compounds as well as quick detection of these microorganisms is necessary to ensure high-quality beverages produced by the brewing industry. In this work, we searched for the presence of two main hop-resistance genes, horA and ORF5, and determined the capacity of four strains of Pediococcus damnosus isolated from a brewery environment to grow in the presence of increasing concentrations of iso-α-acids. All strains were able to grow in increasing concentrations of iso-α-acids up to 150 μg mL À1 . This amount is 10 times greater than the concentration in average beer. Genetic amplification of genes associated with hop-resistance, demonstrated the presence of horA, but not ORF5 in all tested strains. This communication represents the first report of the presence of horA gene in bacteria isolated from breweries in our country.

There are many advantages to using liquid cultures for the production of blastospores. These include mainly the processes of scale up which are relatively easy, as well as the control of parameters such as temperature, aeration and pH. In this work, we evaluated the production of Paecilomyces fumosoroseus blastospores using a low-cost liquid culture medium in a fermenter in comparison to a medium commonly used for this purpose, with regard to yield and viability of blastospores. The two media contained the same concentration of glucose but differed in N source (M1 containing casamino acids and M2 provided with collagen peptone and yeast extract). Starting with an inoculum of 1x10 6 blastospores/ml, M2 medium produced 2x10 10 blastospores/ml after incubation for 72 h at 520 rev/min agitation and 1 v/v/m (volume air/volume liquid.min) aeration, while only 2.4 x 10 8 /ml were produced with M1. In addition, the microorganisms in medium M1 grew more slowly during log phase and reached an earlier plateau at 36 h fermentation. The medium containing collagen peptone and yeast extract is an excellent alternative for the production of P. fumosoroseus blastospores, providing lower cost, higher yield and shorter propagation time, but formulation does need to be improved.

The aim of this study was to evaluate the production of blastospores and conidia of different native isolates and a strain of Isaria fumosorosea using different propagation techniques. Two liquid culture media of casamino acids and peptone as nitrogen sources and glucose as carbon source for both media cultures were respectively used in the production of blastospores, while for the production of conidia, the fungi were grown in potato dextrose agar; from these cultures, solutions of conidia to a concentration of 1×10 per milliliter were prepared to inoculate flasks with Sabouraud dextrose broth for the liquid phase of the biphasic culture, also known as preculture. Subsequently, rice grain bags were inoculated with the preculture and the conidia solutions, which were incubated for 14 days for solid fermentation and biphasic culture, respectively. The HIB-23 isolate recorded a concentration of 4.90×10 blastospores/ml in the casamino acid medium, while a concentration of 2.15×10 blastospores/ml was obtained in the peptone collagen medium. For the Pfr-612 strain, the conidia production in solid-state fermentation was 1.58×10 conidia/g, and for HIB-30 in the biphasic culture of 9.00×10 conidia/g. Solid-state fermentation proved to be the most effective method with an average of 1.09×10 conidia/g, whereas the biphasic culture was the least effective method with 2.76×10 conidia/g; no significant difference was reported for the submerged production media.