microbial responses to environmental factors

BIOL 351, exam 1

osmotolerant

able to grow over wide ranges of water activity or osmotic concentration

halophile

requires high levels of sodium chloride

• usually above about 0.2 M to grow

acidophile

growth optimum between pH 0 and 5.5

neutrophile

growth optimum between pH 5.5 and 8.0

alkalophile

growth optimum between pH 8.0 and 11.5

psychorophile

• grows at 0°C

• an optimum growth temperature of 15°C or lower

psychrotroph

• can grow at 0-7°C

• has an optimum between 20 and 30°C and a maximum around 35°C

mesophile

has growth optimum between 20-45°C

thermophile

• can grow at 55°C or higher

• growth optimum often between 55 and 65°C

hyperthermophile

has an optimum between 85 and about 113°C

obligate aerobe

completely dependent on atmospheric O₂ for growth

facultative anaerobe

does not require O₂ for growth but grows better in its presence

aerotolerant anaerobe

grows equally well in presence or absence of O₂

obligate anaerobe

does not tolerate O₂ and dies in its presence

microaerophile

requires O₂ levels between 2-10% for growth and is damaged by atmosphere O₂ levels (20%)

barophile

growth more rapid at high hydrostatic pressures