Optimizacija priprave spor Bacillus subtilis na odpadkih živilske industrije

Drolc, Leja (author), Štefanič, Polonca (mentor)

Bakterija Bacillus subtilis je zelo zanimiva za biotehnološko industrijo, saj z njo pridobivamo številne produkte kot so antibiotiki, encimi, vitamini. Gojenje bakterije po navadi poteka na dragih komercialnih gojiščih. Cilj diplomske naloge je bil preveriti rast bakterije Bacillus subtilis na odpadkih živilske industrije in s tem poiskati potencialna nadomestila za komercialna gojišča. Rast bakterije Bacillus subtilis smo preverjali na ječmenovih tropinah, sojini moki in sirotki. Bakterijsko kulturo smo inokulirali v substrate in nato smo vsak dan s štetjem kolonij določevali koncentracijo bakterijskih celic in spor. Rezultati so pokazali, da bakterija Bacillus subtilis uspešno raste v vseh treh preiskovanih substratih, celice in spore se namreč pojavljajo v visokih koncentracijah. Najbolj ustrezen substrat so bile ječmenove tropine, kjer smo določili največje skupno število spor in celic, kot tudi spor, nekoliko nižjo rasto smo opazili v sirotki, kjer je bilo skupno število celic in spor 10x nižje, medtem ko je bilo spor 100x manj. V sojini moki, ki je vsebovala najvišje količino že prisotnih bakterij (107 CFU/g), je tretji dan eksperimenta prišlo do znatnega znižanja koncentracije bakterijskih spor, kar je lahko posledica prisotnosti inhibitornih bakterij, zato ta substrat ni primeren za pripravo spor. V nalogi smo pokazali, da so odpadki živilske industrije lahko dober nadomestek dražjim bakterijskim gojiščem in bi v prihodnosti lahko znižali stroške gojenja bakterij, vendar je potrebno za vsak odpadek posebej določiti ustreznost uporabe.

• Language: Slovenian
• Keywords: Bakterija, Bacillus subtilis, optimizacija, rast, odpadki živilske industrije
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Year: 2023
• PID: 20.500.12556/RUL-149084
• COBISS.SI-ID: 163206403
• Publication date in RUL: 03.09.2023

Secondary language

• Language: English
• Title: Optimization of Bacillus subtilis spore preparation on food industry waste

Abstract

Bacillus subtilis is of great interest to the biotechnology industry, as it is used to produce many products such as antibiotics, enzymes and vitamins. The aim of this thesis was to test the growth of Bacillus subtilis on waste from the food industry in order to find potential alternatives to commercial media. The growth of Bacillus subtilis was tested on brewer’s spent grain, soybean flour and whey. The bacterial culture was inoculated into the substrates and then the concentration of bacterial cells and spores was determined daily by colony counting. The results showed that Bacillus subtilis grew successfully in all three substrates tested, with cells and spores occurring in high concentrations. The most suitable substrate was brewer's spent grain, where the highest total number of spores and cells as well as spores was determined, while a slightly lower growth was observed in whey, where the total number of cells and spores was 10x lower, while the number of spores was 100x lower. In soybean flour, which contained the highest amount of bacteria already present (107 CFU/g), there was a significant decrease in the concentration of bacterial spores on the third day of the experiment, which may be due to the presence of inhibitory bacteria, and therefore this substrate is not suitable for spore preparation. In this thesis we have shown that food industry waste can be a good substitute for more expensive bacterial media and could reduce the cost of bacterial cultivation in the future, but the suitability of use needs to be determined on a waste-by-waste basis.

• Keywords: Bacteria, Bacillus subtilis, optimisation, growth, food industry waste