title: Simultaneous single-cell protein production and COD removal with characterization of residual protein and intermediate metabolites during whey fermentation by K. marxianus.
abstract: Cheese whey fermentation with Kluyveromyces marxianus was carried out at 40 °C and pH 3.5 to examine simultaneous single-cell protein production and chemical oxygen demand (COD) removal, determine the fate of soluble whey protein and characterize intermediate metabolites. After 36 h of batch fermentation, the biomass concentration increased from 2.0 to 6.0 g/L with 55 % COD reduction (including protein), whereas soluble whey protein concentration decreased from 5.6 to 4.1 g/L. It was confirmed through electrophoresis (SDS-PAGE) that the fermented whey protein was different from native whey protein. HPLC and GC-MS analysis revealed a change in composition of organic compounds post-fermentation. High inoculum concentration in batch fermentation resulted in an increase in biomass concentration from 10.3 to 15.9 g/L with 80 % COD reduction (including protein) within 36 h with residual protein concentration of 4.5 g/L. In third batch fermentation, the biomass concentration increased from 7.3 to 12.4 g/L with 71 % of COD removal and residual protein concentration of 4.3 g/L after 22 h. After 22 h, the batch process was shifted to a continuous process with cell recycle, and the steady state was achieved after another 60 h with biomass yield of 0.19 g biomass/g lactose and productivity of 0.26 g/L h. COD removal efficiency was 78-79 % with residual protein concentration of 3.8-4.2 g/L. The aerobic continuous fermentation process with cell recycle could be applied to single-cell protein production with substantial COD removal at low pH and high temperature from cheese whey.
authors.affiliation: Centre Eau, Terre et Environnement, Institut National de la Recherche Scientifique, Université du Québec, 490 de la Couronne, Quebec, QC, G1K 9A9, Canada.
authors.forename: J S S
authors.initials: JS
authors.lastname: Yadav
authors.forename: J
authors.initials: J
authors.lastname: Bezawada
authors.forename: S
authors.initials: S
authors.lastname: Elharche
authors.forename: S
authors.initials: S
authors.lastname: Yan
authors.forename: R D
authors.initials: RD
authors.lastname: Tyagi
authors.forename: R Y
authors.initials: RY
authors.lastname: Surampalli
mesh_terms: D000332:Aerobiosis / Q000502:physiology; D018533:Biomass; D002611:Cheese / Q000382:microbiology; D005285:Fermentation / Q000502:physiology*; D007716:Kluyveromyces / Q000254:growth & development*; D010101:Oxygen Consumption / Q000502:physiology