Direct fermentation of potato starch to ethanol by cocultures of Aspergillus niger and Saccharomyces cerevisiae

Abstract

Direct fermentation of unhydrolyzed potato starch to ethanol by monocultures of an amylolytic fungus, Aspergilus niger, and cocultures ofA. niger and Saccharomyces cerevisiae was investigated. Amylolytic activity, rate and amount of starch utilization, and ethanol yields increased several-fold in coculture versus the monoculture due to the synergistic metabolic interactions between the species. Optimal ethanol yields were obtained in the pH range 5 to 6 and amylolytic activity was obtained in the pH range 5 to 8. Ethanol yields were maximal when fermentations were conducted anaerobically. Increasing S. cerevisiae inoculum in the coculture from 4 to 12% gave a dramatic increase in the rate of ethanol production, and ethanol yields of >96% of the theoretical maximum were obtained within 2 days of fermentation. These results indicate that simultaneous fermentation of starch to ethanol can be conducted efficiently by using cocultures of the amylolytic fungus A. niger and a nonamylolytic sugar fermenter, S. cerevisiae.

Effects of solid‐state fermentation (Aspergillus oryzae var. oryzae) on the physicochemical properties of corn starch

“…Commonly, SSF is conducted by fungi over starch‐rich substrates. Ethanol production , traditional food , citric acid production , and koji fermentation are instances of fungi‐based fermentation processes of starchy matrices. Commonly used fungi strains for SSF include Aspergillus oryzae traditionally used for koji production, and Penicillium roquefortii for cheese production .…”

Bioconversion of cassava starch to ethanol in a simultaneous saccharification and fermentation process by co-cultures of <i>Aspergillus niger</i> and <i>Saccharomyces cerevisiae</i>.

“…In such a process, two organisms with synergistic relationships are co-cultured together in the same vessel. A study has shown that co-culturing of an efficient sugar fermenter such as Saccharomyces cerevisiae with an Aspergillus species in a starch medium would prevent accumulation of inhibitory concentrations of reducing sugar and hence, an enhancement of the amylolytic activity, the amount of starch metabolizable, and the total ethanol yield (Abouzied & Reddy, 1986).…”

Candida tropicalis BPU1 produces polyhydroxybutyrate on raw starchy substrates

“… where, Y represents the response variable, β 0 , β i , β ii , β ij are intercept, linear, quadratic, and interaction constant coefficients, respectively, and k is the numbers of involved variables. The residual starch was also determined for each trials employing phenol–sulphuric acid method .…”