Valorization of kitchen biowaste for ethanol production via simultaneous saccharification and fermentation using co-cultures of the yeasts Saccharomyces cerevisiae and Pichia stipitis

Abstract

The biotransformation of the pre-dried and shredded organic fraction of kitchen waste to ethanol was investigated, via co-cultures of the yeasts Saccharomyces cerevisiae and Pichia stipitis (Scheffersomyces stipitis). Preliminary experiments with synthetic media were performed, in order to investigate the effect of different operational parameters on the ethanol production efficiency of the co-culture. The control of the pH and the supplementation with organic nitrogen were shown to be key factors for the optimization of the process. Subsequently, the ethanol production efficiency from the waste was assessed via simultaneous saccharification and fermentation experiments. Different loadings of cellulolytic enzymes and mixtures of cellulolytic with amylolytic enzymatic blends were tested in order to enhance the substrate conversion efficiency. It was further shown that for solids loading up to 40% waste on dry mass basis, corresponding to 170 g.L initial concentration of carbohydrates, no substrate inhibition occurred, and ethanol concentration up to 45 g.L was achieved.

Utilization of Fruit Waste for Bioethanol Production by Co-cultures of Aspergillus niger and Saccharomyces cerevisiae

“…Optimal fermentation temperature has been widely reported in the range of 30-38ºC [4,7,[9][10][11]16]. In addition, the use of co-cultures has also been studied as a means of further increasing ethanol yield [17][18][19][20][21][22]. This provides an alternative fermentation path when biomass high in lignocellulose is used as feedstock [17].…”

“…This provides an alternative fermentation path when biomass high in lignocellulose is used as feedstock [17]. For bio-wastes, co-cultures of yeasts (Saccharomyces cerevisiae and Pichia stipites) achieved ethanol concentrations up to 45 g L -1 [18]. Until recently, co-cultures for simultaneous saccharification and cofermentation employed combinations of bacteria and yeast [17,19], yeast and yeast [18,20] or fungi and yeast [21][22], depending on substrate and fermentation conditions.…”

Performance assessment of a four-air cathode membraneless microbial fuel cell stack for wastewater treatment and energy extraction

“…Following the inoculation period glucose was replaced by FORBI extract, without further addition of sludge and trace elements. FORBI was produced by drying and shredding the pre-sorted fermentable fraction of household food waste collected door-to-door in the Municipality of Halandri, Athens, Greece [16,17,20]. The electrode output for each MFC was individually recorded, at 1min intervals, in volts (V) versus time using a data acquisition system (Advantech ADAM-4019+) [17].…”

Operation and Electro(chemical) characterization of a microbial fuel cell stack fed with fermentable household waste extract

“…Following the inoculation period glucose (three batch cycles) was replaced by FORBI extract (0.8 g COD L -1 ), without further addition of sludge. FORBI was produced by drying and shredding the pre-sorted fermentable fraction of household food waste collected door-to-door in the Municipality of Halandri, Athens, Greece (Chatzikonstantinou et al, 2018;Ntaikou et al, 2018;Tremouli et al, 2019).…”

“…The stack was fed with a water extract from fermentable household food waste (FORBI) (0.8 g COD L -1 ) as substrate. FORBI was produced by household food waste collected from the Municipality of Halandri, Athens, Greece (Chatzikonstantinou et al, 2018;Ntaikou et al, 2018). Measurements included Open Current Voltage (OCV) data recording, Linear Sweep Voltammetry (LSV) curves and Electrochemical Impedance Spectroscopy (EIS) characterization under parallel and series electrical connection of the stack.…”