Abstract
The novelty of this study lies in the integration of fermentation in a magnetically stabilized fluidized bed bioreactor with S. cerevisiae supported on calcium alginate with magnetic particles and using levoglucosan, a pyrolytic sugar from sugarcane bagasse, as a substrate for bioethanol production. Sugarcane bagasse was pretreated with acetic acid to remove alkali/alkaline earth metals (AAEMs) aiming to intensify levoglucosan production in the bio-oil prior pyrolysis at 400 °C in an Auger reactor. Subsequently, the levoglucosan extracted from the bio-oil was hydrolyzed with H₂SO₄ and partially detoxified to use the resulting extract as substrate. Fermentations were carried out in the bioreactor operating in magnetically stabilized bed mode with axial magnetic field lines at 12 kA/m. The fermentation kinetics were monitored by substrate consumption and ethanol production over 8h under anaerobic conditions. When glucose was used as substrate (control experiments), the results revealed that the magnetic field induced a higher sugar consumption rate and bioethanol productivity of 5.8 gL −1 h −1 , achieving a fermentative efficiency of 97.44%, since the fermentation time was reduced by approximately 2h compared to fermentations without the application of a magnetic field. However, when hydrolyzed levoglucosan extract was evaluated, the fermentative efficiency was 91.57%, approximately 6.5% lower when compared to the control experiment. This could occur due to the presence in the fermentation medium of traces of pyrolytic derivatives, which are known inhibitors of cellular activity. Furthermore, the stimulatory effect of the magnetic field on process productivity is consistent with data previously reported in studies with yeast cells during alcoholic fermentations, thus corroborating the potential of this technology as an alternative process for bioethanol production on a bench scale.