title: Flocculation and haze removal from crude beer using in-house produced laccase from Trametes versicolor cultured on brewer's spent grain.
abstract: The potential of brewer's spent grain (BSG), a common waste from the brewing industry, as a support-substrate for laccase production by the well-known laccase producer Trametes versicolor ATCC 20869 under solid-state fermentation conditions was assessed. An attempt was made to improve the laccase production by T. versicolor through supplementing the cultures with inducers, such as 2,2-azino bis(3-ethylbenzthiazoline-6-sulfonic acid), copper sulfate, ethanol, gallic acid, veratryl alcohol, and phenol. A higher laccase activity of 13506.2 ± 138.2 IU/gds (gram dry substrate) was obtained with a phenol concentration of 10 mg/kg substrate in a tray bioreactor after 12 days of incubation time. The flocculation properties of the laccase treated crude beer samples have been studied by using various parameters, such as viscosity, turbidity, ζ potential, total polyphenols, and total protein content. The present results indicated that laccase (25 IU/L) showed promising results as a good flocculating agent. The laccase treatment showed better flocculation capacity compared to the industrial flocculation process using stabifix as a flocculant. The laccase treatments (25 IU/L) at 4 ± 1 °C and room temperature have shown almost similar flocculation properties without much variability. The study demonstrated the potential of in-house produced laccase using brewer's spent grain for the clarification and flocculation of crude beer as a sustainable alternative to traditional flocculants, such as stabifix and bentonite.
authors.affiliation: INRS-ETE, Université du Québec, Québec, Canada.
authors.forename: Gurpreet Singh
authors.initials: GS
authors.lastname: Dhillon
authors.forename: Surinder
authors.initials: S
authors.lastname: Kaur
authors.forename: Satinder Kaur
authors.initials: SK
authors.lastname: Brar
authors.forename: Mausam
authors.initials: M
authors.lastname: Verma
mesh_terms: D001515:Beer / Q000032:analysis*; D003470:Culture Media; D002523:Edible Grain / Q000378:metabolism*; D005285:Fermentation; D005427:Flocculation; D005511:Food Handling / Q000379:methods*; D042845:Laccase / Q000096:biosynthesis* / Q000378:metabolism; D055454:Trametes / Q000201:enzymology* / Q000254:growth & development*
chemical_list: D003470:Culture Media; D042845:Laccase