Extracellular amylases of starch-fermenting yeast: pH effect on export and residence time in the periplasm

Journal Article · Wed Dec 31 23:00:00 EST 1986 · CRC Crit. Rev. Biotechnol.; (United States)

DOI:https://doi.org/10.3109/07388558709086976· OSTI ID:5564704

Calleja, G B; Levy-Rick, S R; Nasim, A; Lusena, C V

Aerobic cultures of S. alluvius in Wickerham's yeast-nitrogen-base medium with starch as sole carbon source become strongly acidic and contain no detectable extra-cellular amylolytic activity during stationary phase, when the activity in buffered cultures is maximal. The extracellular amylases are irreversibly inactivated at the low pH value (less than 3.5) attained by the cultures. When adequately buffered, the medium yields maximal extracellular amylolytic activity. About 0.2 M phosphate buffer is adequate for substrate concentrations of up to 0.5% starch; higher starch concentrations require more buffer. Unbuffered cultures that are adjusted once with alkali to pH 5.5 also allow maximal extracellular amylolytic activity, provided the adjustment is made prior to the end of exponential growth. Automatic pH control allows use of high starch concentrations of up to 4%. Export is optimal at pH values higher than the optima for enzyme activity and stability and for population growth. The need for pH adjustment prior to the appearance of amylolytic activity in the medium suggests pH dependence of the export process itself and/or acid inactivation of enzymes transiently resident in the periplasm. (Refs. 23).

• Research Organization: National Research Council of Canada, Ottawa, Canada. Molecular Genetics Section, Division of Biological Sciences
• OSTI ID: 5564704
• Journal Information: CRC Crit. Rev. Biotechnol.; (United States), Journal Name: CRC Crit. Rev. Biotechnol.; (United States) Vol. 5:3; ISSN CRBTE
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
140504* -- Solar Energy Conversion-- Biomass Production & Conversion-- (-1989)
AEROBIC CONDITIONS
AMYLASE
BUFFERS
CARBOHYDRATES
CELL CULTURES
ENZYME ACTIVITY
ENZYMES
FUNGI
GLYCOSYL HYDROLASES
HYDROLASES
MICROORGANISMS
O-GLYCOSYL HYDROLASES
ORGANIC COMPOUNDS
PH VALUE
PLANTS
POLYSACCHARIDES
REAGENTS
SACCHARIDES
STARCH
YEASTS