Preparation and performance of immobilized yeast cells in columns containing no inert carrier

Abstract

Schizosaccharomyces pombe was cultivated in a medium of glucose (10 g/L) malt extract (3 g/L), yeast extract (3 g/L), and bactopeptone (5 g/L) to form flocs. More than 95% of the cell population were flocculated. Variation in glucose concentration (from 10 to 100 g/L) did not affect flocculation. Yeast extract helped induce flocculation. Application of the immobilized yeast for the continuous production of ethanol was tested in a column reactor. Soft yeast flocs (50-200 mesh) underwent morphological changes to heavy particles (0.1-0.3 cm diameter) after continuously being fed with fresh substrates in the column. Productivity as high as 87 g EtOH L(-1) h(-1) was obtained when a 150 g/L glucose medium was fed. The performance of this yeast reactor was stable over a two-month period. The ethanol yield was 97% of the theoretical maximum based upon glucose consumed.

Must deacidification with an induced flocculant yeast strain of Schizosaccharomyces pombe

“…Unlike the case described by Hsiao et al (1983) flocculation could not be induced in a batch culture for the strain used in this work. The aggregates obtained by this process were only visible microscopically, and they were not able to settle d o w n in the growth m e d i u m .…”

“…The induction of flocculation ability in a strain of Schizosaccharomyces pombe, using the medium of Hsiao et al (1983) and an external loop reactor is described in this work (Mota and Teixeira 1990). The performance of the bioreactor in the deacidification of a synthetic medium or grape must was studied.…”

“…Schematic representation of the external loop reactorInduction of flocculation in batch culture. The procedure described byHsiao et al (1983) was adopted to attempt the induction of flocculation in batch culture.…”

Development of a biofilm bioreactor for enhanced ethanol production

“…Schizosaccharomyces pombe, a naturally flocculating yeast, was cultivated in a column reactor to be used for continuous ethanol production by Hsiao and co-workers (40). An ethanol productivity of 87 g/l/h was reported with a feed of 150 g/1 of glucose.…”