Repeated fermentation from raw starch using Saccharomyces cerevisiae displaying both glucoamylase and α-amylase

Efficient co-displaying and artificial ratio control of α-amylase and glucoamylase on the yeast cell surface by using combinations of different anchoring domains

“…In previous studies, the C-terminal domain of α-agglutinin (Sag1), which is a GPI protein in Saccharomyces cerevisiae, has been mainly used as an anchoring domain in fusion proteins (Murai et al 1999;Yamada et al 2010b;Yamakawa et al 2012). The genes encoding these fusion proteins were expressed by constitutive promoters such as TDH3 and PGK1 promoters.…”

“…Because the recovery of the biocatalyst from the products is easy, reutilization of the yeast cells allows reuse of the active enzymes on its cell surface, without the need for the cells to reproduce. Previously, a yeast strain displaying α-amylase (EC 3.2.1.1) and glucoamylase (1,4-α-D-glucan glucohydrolase; EC 3.2.1.3) on its cell surface was constructed via random integration of the multiple α-amylase and glucoamylase genes into the cell genome (δ-integration) (Yamakawa et al 2012). The displayed enzyme activities of the strain were stably maintained even after 23 cycles of repeated batch fermentations.…”

Single-step production of polyhydroxybutyrate from starch by using α-amylase cell-surface displaying system of Corynebacterium glutamicum

“…The display of glycosidases enables microbes to hydrolyze and simultaneously utilize polysaccharides, such as starch, as a carbon source. Additionally, the displayed enzymes were reported to maintain the activity during long time cultivation (14) that could be an advantage over the enzyme-secreting system. Therefore in this study, we attempt to produce PHB from starch using an engineered C. glutamicum strain HPA displaying α-amylase from…”

Construction of Amylolytic Industrial Strains of Saccharomyces cerevisiae for Improved Ethanol Production from Raw Starch

“…The reduction in energy requirements during the gelatinization process achieved by using RSDE has been currently exploited for the commercial production of ethanol (Sun et al, 2010). To reduce the costs of ethanol production from raw starch, it may prove necessary to improve the rate of ethanol fermentation by increasing the activities of both raw starch degrading glucoamylase and raw starch degrading α -amylase (Yamada et al, 2012). Concerted efforts by multi-national research teams can be attainable to construct recombinant yeast strains which are capable of converting raw starch to glucose within 48-72 h, to a final ethanol concentration in excess of 10% in the near future (van Zyl et al, 2012).…”

“…For industrial-scale fermentation, ethanol productivity from raw starch depends on the improvement of amylase activities (Yamada et al, 2009(Yamada et al, , 2010. Manipulation of S. cerevisiae to expresses high RSDE activities, via δ-integration and rDNA-integration of the RSDE genes, can be useful for the improvement of ethanol productivity from raw starch (Kim et al, 2011;Yamada et al, 2012). We recently constructed δ -integrative and rDNA-integrative vectors to allow for the multiple integration of amylase genes into the chromosomes of industrial strains (Ghang et al, 2007;Kim et al, 2010).…”