Abstract
Anaerobic fermentation of organic compounds is used in many biotechnological processes and has been the subject of much research. A variety of process conditions and different growth media can be used to obtain microbial metabolites. The media must be free from contamination before fermentation. Sterilization is most often achieved by applying heat or other treatments, such as ozonation. Sterilization of liquid media using ozone can be very beneficial, but this method introduces high concentrations of residual oxygen, which inhibit anaerobic processes. Deoxidation is therefore necessary to remove the oxygen from ozonated broths. This study evaluates the effectiveness of three deoxidation agents for two kinds of fermentation media based on malt or molasses: ultrasound, iron(II) sulfate, and Metschnikowia sp. yeast. The time needed for deoxidation varied, depending on the kind of broth and the deoxidation agent. In general, the dynamics of oxygen removal were faster in malt broth. A comparative analysis showed that yeast biomass was the most effective agent, achieving deoxidation in the shortest time. Moreover, the fully deoxidated broth was supplemented with yeast biomass, which is rich in biogenic substrates, expressed as a protein content of 0.13–0.73 g/L. Application of Metschnikowia sp. may therefore be considered as an effective strategy for simultaneous deoxidation and nutrient supplementation of broths used in anaerobic biotechnological processes.
Highlights
IntroductionMicrobial contamination can affect the yields from all types of fermentation media
Microbial contamination can affect the yields from all types of fermentation media.The conventional method of decontamination is heat sterilization
Samples of the Malt broth (MB) and molasse broth (MSB) broths were placed in a 500 mL glass reactor and subjected to ultrasonification using a UP400S ultrasonic device (Hielscher, Teltow, Germany)
Summary
Microbial contamination can affect the yields from all types of fermentation media. The conventional method of decontamination is heat sterilization. The type and quantity of the contamination, as well as the composition of the media, may have an important influence on its effectiveness. Heat treatment is an energy-intensive process, which requires special equipment and is chemically invasive. During the production of molasses-based broths, undesirable changes in the composition of the broth may occur, in particular the sedimentation of colloids or the appearance of melanoidins—dark brown products of the condensation of sugars and amino acids produced by Maillard reactions [1]. New methods of sterilization are sought that are effective, cost-comparable, and safe for the environment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
