Year: 2010
Type: dissertation
Abstract: The new sugar reform in EU has lead to a reduced price on sugar, and consequently on sugar beets produced for sugar production in Sweden.The high content of convertible carbohydrates in sugar beets make them suitable for bioenergy production and the price on sugar beets would not change if they are used in a bioenergy purpose.Thus, the sugar beet production in Sweden would still be profitable.The limiting factor is the short storage capability of sugar beets, and to be able to use them for a longer period, the storage time needs to be prolonged.Biogas and bioethanol are both renewable energy sources and seen as promising alternative fuels.Biogas is produced through anaerobic digestion of a wide range of organic materials, while bioethanol mainly is produced from different sugar crops and grains by fermentation.Previously the biopreservation organisms Pseudomonas fluoresence KJ36 and Candida oleophila JÄ3 had been isolated from sugar beets and shown to inhibit various fungal pathogens on agar medium.Hoping to prolong the storage time for sugar beets, a model scale storage study was set up with the biocontrol organisms Candida oleophila JÄ3 and Pseudomonas fluoresence KJ36.Small cubes of sugar beets were stored for one and four months at 10°C and 15°C.Microbial growth during storage was determined trough viable count and the effect of the biocontrol organisms was then analysed with regard to biogas and ethanol production through anaerobic digestion and fermentation experiments.To evaluate the effect of the biocontrol microorganisms on sugar content during storage, sucrose, glucose and fructose concentrations were determined through HPAEC-PAD analysis.From this study, it can be concluded that the biopreservation organisms Pseudomonas fluoresence KJ36 and Candida oleophila JÄ3 did not to inhibit various fungal pathogens.The endogenous bacteria increased in number and consequently do not seem to be affected by biopreservation organisms on the surface of the sugar beet cubes.Neither was mould growth on the surface inhibited.Consequently, the effect on sugar content and therefore also on the ethanol production potential was negative.The biocontrol and spoilage organisms have decreased the yield by decreasing the sugar content and subsequent ethanol yield from samples stored for four months.The biogas production from the beet samples decreased with storage time due to the consumption of organic material by the biocontrol and spoilage organisms.The storage time of sugar beets cannot be prolonged using the biocontrol organisms Pseudomonas fluoresence KJ36 and Candida oleophila JÄ3.
Author: Katarina Örning
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2401646611