Marine yeast isolation and application in beer brewing

U ovom radu se istražuju mogućnosti fermentacije kvasaca izoliranih iz mora radi upotrebe u pivarstvu. Uzorci mora su uzeti na priobalnoj postaji srednjeg Jadrana u siječnju pri temperaturi mora od 12°C. Za izolaciju uzorkovanih kvasca korištene su četiri hranjive podloge predviđene za rad s kvascima: yeast-malt (YM) agar, YM agar s antibiotikom, zakiseljeni YM agar i Sabouraud dextroza agar (SDA). Uspješno je izolirano 16 vrsta kvasaca od kojih su tri vrste bile pozitivne na testu fermentacije. Pozitivne vrste su determinirane fiziološkim testom API® ID 32 C koji se koristi za brzu determinaciju ATCC sojeva kvasca. Od tri determinirane fermentativne vrste, Candida famata je u potpunosti fermentirala pivo do konačnog proizvoda, Candida pelliculosa je sporo fermentirala u zadanom vremenskom periodu, a Candida sake nije fermentirala pivo.This master thesis investigates the possibilities of fermentation of marine yeasts isolated from the central Adriatic Sea for use in the brewing process. Sea samples were taken in January at a sea temperature of 12°C. Four nutrient media designed for yeasts isolation and growth were used to isolate sampled yeasts from marine samples: yeast-malt (YM) agar, YM agar with antibiotics, acidified YM agar and Sabouraud-dextrose agar. Sixteen colonies of yeasts were successfully isolated, and only three of them were positive in the fermentation test. Positive yeast colonies were identified by API® ID 32 C physiological test used for rapid determination of ATCC strains of yeast. From the three identified fermentative species, Candida famata fermented the beer entirely. Candida pelliculosa fermented slowly over a given period, while Candida sake did not ferment the beer at all. Marine yeast isolates show potential for the brewing process