Biosinteza i karakterizacija bakterijske nanoceluloze uzgojene u statičnim uvjetima u soku od borovnica

master's thesis

• Title (english): Biosynthesis and characterization of bacterial nanocellulose from static cultivation in blueberry juice
• Author: Vili Nemec
• Mentor: Sunčica Beluhan (mentor)
• Committee member: Ksenija Markov (član povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for Biochemical Engineering, Industrial Microbiology and Malting and Brewing Technology); Zagreb
• Defense date and country: 2020-09-29, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Bakterijska nanoceluloza (BNC) je održivi prirodni egzopolisaharid, kojeg karakteriziraju izvrsna svojstva, kao što su hidrofilnost, biorazgradivost, velika sposobnost kemijske modifikacije, te sposobnost oblikovanja različitih polukristaliničnih morfologija. Tijekom 21 dana fermentacije kombuche u soku od borovnica u aerobnim uvjetima, uz dodatak 40 do 120 g/L saharoze, praćene su promjene pH vrijednosti, kinetika nastajanja organskih kiselina (octene, glukonske, mliječne i glukuronske), etanola i prinos sintetizirane BNC. Smanjenje pH vrijednosti posljedica je simbiotičko-metaboličkih aktivnosti osmofilnih kvasaca i bakterija octene kiseline i nastajanja organskih kiselina. Debljina i prinos BNC se povećavala tijekom fermentacije. Uzorci su analizirani FT-IR spektroskopijom te je utvrđeno da su svi imali visoki postotak kristaliničnosti. Uočena je antimikrobna aktivnost BNC prema bakterijama Escherichia coli, Salmonella typhimurium, i Pseudomonas aeruginosa i kvascu Candida albicans, ali ne i prema bakterijama Vibrio cholerae i Staphylococcus aureus.

Abstract (english)

Bacterial nanocellulose (BNC) is a sustainable natural egzopolysaccharide characterized by excellent properties such as hydrophilicity, biodegradability, broad chemical-modifying capacity, and the formation of different semicrystalline fiber morfologies. Changes in pH value, the formation of organic acids (acetic, gluconic, lactic, and glucuronic), ethanol and synthesized BNC yield were observed over a period up to 21 days of fermentation in sucrose-sweetened blueberry juice (40 to 120 g/L). Altering in pH was due to the symbiotic metabolic activity of osmophilic yeast and acetic acid bacteria and declined with the formation of organic acids. The BNC thickness and yield increased with fermentation time. Analyzing samples by FT-IR spectroscopy, it was detected that all samples had a higher percentage of crystallinity. Antimicrobial activity was observed against bacteria Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, and yeast Candida albicans, but not against the bacteria Vibrio cholerae and Staphylococcus aureus.

• Keywords: kombucha; organske kiseline; bakterijska nanoceluloza (BNC); karakterizacija; antimikrobna aktivnost
• Keywords (english): Kombucha; Organic acids; Bacterial nanocellulose (BNC); Characterization; Antimicrobial activity
• Language: croatian
• URN:NBN: urn:nbn:hr:159:611042
• Study programme: Title: Molecular Biotechnology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka molekularne biotehnologije (magistar/magistra inženjer/inženjerka molekularne biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-01-20 12:38:39