Simultaneous degradation of phytic acid and starch by an industrial strain of Saccharomyces cerevisiae producing phytase and α-amylase

Abstract

Phytase liberates inorganic phosphate from phytic acid (myo-inositol hexakisphosphate) which is the major phosphate reserve in plant-derived foods and feeds. An industrial strain of Saccharomyces cerevisiae expressing the Debaryomyces castellii phytase gene (phytDc) and D. occidentalis alpha-amylase gene (AMY) was developed. The phytDc and AMY genes were constitutively expressed under the ADC1 promoter in S. cerevisiae by using the delta-integration system, which contains DNA derived exclusively from yeast. The recombinant industrial strain secreted both phytase and alpha-amylase for the efficient degradation of phytic acid and starch as main components of plant seeds. This new strain hydrolyzed 90% of 0.5% (w/v) sodium phytate within 5 days of growth and utilized 100% of 2% (w/v) starch within 48 h simultaneously.

Probiotic Potential of Yeasts Isolated From Traditional Indian Fermented Foods

“…In this investigation, allof the seven isolates were phytase producers. A number of yeasts are known to produce phytase such as Candida krusei, Schwanniomyces castellii, Debaryomyces castellii, Arxula adeninivorans, Pichia sp., Cryptococcus laurentii, Rhodotorula gracilis and S. cerevisiae [25,61,62] etc. Two probiotic yeasts isolated from sea cucumber Holothuria scabra namely, Yarrowia lypolytica and Candida tropicalis, have been reported to produce phytase [63].…”

Phytases: crystal structures, protein engineering and potential biotechnological applications

“…They created a P. pastoris that expressed the modified phytase gene (phy‐pl‐sh), with the MF4I sequence producing 12·2 g of phytase per litre of fluid culture and a phytase activity of 10540 U ml −1 . Using the phytase gene (phytDc) from D. castellii and an alpha‐amylase gene (AMY) from Debaryomyces occidentalis as the target genes, Lim et al. (2008) developed an industrial strain of S. cerevisiae .…”

Construction of a direct starch-fermenting industrial strain of Saccharomyces cerevisiae producing glucoamylase, α-amylase and debranching enzyme

“…1) and the unneeded sequences related to bacterial DNA and ampicillin resistance marker (2.8 kb) were removed to produce a smaller linear vector prior to transformation. These resulting fragments (8.2 kb) containing the ADC1p-GA1 and ADC1p-AMY gene cassettes flanked by d sequences could be integrated into d sequences dispersed throughout the S. cerevisiae genome to produce multicopy integrants (Ghang et al 2007;Lim et al 2008). The GAM1 gene was separately introduced into S. cerevisiae targeted to the rDNA sequences since d-integrative system containing GA1, AMY and GAM1 gene cassettes (13 kb) could exhibit lower amylolytic activity and mitotic stability, possibly because of low copy integrations by long integrating constructs (data not shown).…”

“…Plasmid YIpAURG1 and YIpdAURSGd (Ghang et al 2005(Ghang et al , 2007 were used to clone the GA1 gene and GAM1 gene, respectively. YIpdAURDpSAd and YIpGB2 (Choi et al 2002;Lim et al 2008) served as the backbones of the d-integrative system and the 18S rDNA-integrative system, respectively.…”