title: Cell-recycle batch process of Scheffersomyces stipitis and Saccharomyces cerevisiae co-culture for second generation bioethanol production.
abstract: OBJECTIVE
  To achieve an optimized co-culture ratio of Scheffersomyces stipitis and Saccharomyces cerevisiae for the production of second generation bioethanol under a cell-recycle batch process.
  
  
  RESULTS
  Three Sacc. cerevisiae strains were evaluated in co-culture with Sch. stipitis CBS 5773 at different ratios using synthetic medium containing glucose and xylose. Bioreactor trials indicated that the optimal condition for ethanol production using Sacc. cerevisiae EC1118 and Sch. stipitis co-culture was 1 % of O2 concentration. To increase ethanol production with Sacc. cerevisiae/Sch. stipitis co-culture a cell-recycle batch process was evaluated. Using this process, the maximum ethanol production (9.73 g l(-1)) and ethanol yield (0.42 g g(-1)) were achieved exhibiting a tenfold increase in ethanol productivity in comparison with batch process (2.1 g l(-1) h(-1)). In these conditions a stabilization of the cells ratio Sacc. cerevisiae/Sch. stipitis (1:5) at steady state condition was obtained.
  
  
  CONCLUSIONS
  Batch cells recycling fermentation is an effective process to use Sch. stipitis/Sacc. cerevisiae co-culture for second generation ethanol production.
authors.affiliation: Dipartimento Scienze della vita e dell'Ambiente (DISVA), Università Politecnica delle Marche, Via Brecce Bianche, 60131, Ancona, Italy.
authors.forename: Selim
authors.initials: S
authors.lastname: Ashoor
authors.affiliation: Dipartimento Scienze della vita e dell'Ambiente (DISVA), Università Politecnica delle Marche, Via Brecce Bianche, 60131, Ancona, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Comitini
authors.affiliation: Dipartimento Scienze della vita e dell'Ambiente (DISVA), Università Politecnica delle Marche, Via Brecce Bianche, 60131, Ancona, Italy. m.ciani@univpm.it.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Ciani
mesh_terms: D061249:Batch Cell Culture Techniques / Q000379:methods*; D056804:Biofuels; D001709:Biotechnology / Q000379:methods*; D005285:Fermentation; D010100:Oxygen; D010843:Pichia / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D056804:Biofuels; D010100:Oxygen
keywords: Bioethanol; Biofuel; Cell recycle; Co-culture; Ethanol production; Saccharomyces cerevisiae; Scheffersomyces stipitis; Second generation bioethanol