Module 4.2 Flashcards
What is the pH range of each classification of organisms based on pH?
Acidophiles < pH 5.4
Neutrophiles pH 5.4 - 8.5
Alkaliphiles pH 7.5 - 11.5
are acid-loving organisms.
< pH 5.4
Acidophiles
acidophiles
(pH 6)
(pH 2 or less)
(pH <4) sulfur-oxidizing bacteria
(negative pH values) archaea
Lactobacillus
Helicobacter pylori
Acidithiobacillus
Sulfolobus and Thermoplasma, Picrophilus
pH 5.4 - 8.5
most human disease-causing bacteria (human blood and tissues pH = 7.2 – 7.4)
protozoans and most bacteria (pH 6.5-7.5)
neutrophiles
neutrophiles
bacteria in gut
protozoan in human large intestines
bacteria on tissue surface
skin infection
- E. coli
- Balantidium coli
- Salmonella
- Staphylococcus
base-loving organisms
live in soda lakes, high-carbonate soils
pH 7.5 - 11.5
alkaliphiles
pH 7.5 - 11.5
Bacillus
Vibrio cholerae (pH 9),
Alcaligenes faecalis (>pH 9),
Agrobacterium (pH 12)
Alkaliphiles
three critical temperatures (affecting enzyme
function) or cardinal temperatures:
minimum growth temperature
optimum growth temperature
maximum growth temperature
Temperature Classes of Microorganisms
Psychrophiles: <0 to 20, 15
Mesophiles 10 to 48, 37
Thermophiles 40 to 72, 60
Hyperthermophiles 65 to 110, 80
Psychrophiles
obligate psychrophiles <20 ̊C
acultative psychrophiles
snow alga
Sporosarcina globispora
Xanthomonas pharmicola
Chlamydomonas nivalis
Psychrophiles
that is present in raw milk and a variety of process meat,
can grow even in cold temp of refrigerator (can multiply at -4.4 ̊C),
can be killed by cooking and pasteurization
Listeria monocytogenes
Mesophiles
thermoduric microorganisms
Bacillus, Micrococcus, Lactococci, Corynebacterium
obligate thermophiles
facultative thermophiles
Geobacillus stearothermophilus
Bacillus coagulans (35-50 ̊C), B. licheniformis
examples of _________:
archaeobacteria (deep-sea vents, 115 ̊C)
Pyrolobus fumarii (“firelobe of the chimney”) – (113 ̊C)
Thermus aquaticus
Hyperthermophiles
Preventing Growth Using Temperature:
refrigeration (4 ̊C) - refrigerator
long-time storage (-30 ̊C) - ultra-low freezer
high temperatures - pressure cooker
Tolerating Low and High Temperatures
unsaturated (polyunsaturated) fatty acids in phospholipids
with enzymes functional at low temperatures
active transport occurs well at low temperatures
Psychrophiles
Tolerating Low and High Temperatures
saturated fatty acids in phospholipids
heat-stable proteins and enzymes
thermophiles
Tolerating Low and High Temperatures
no fatty acids in their membrane (phytane)
lipid monolayer
- in some species, the opposing phospholipid tails are joined into a single tail, forming a monolayer that _______ the membrane at high temperatures
Hyperthermophiles,
stabilizes
microorganisms can be classified as (based on oxygen chuchu)
obligate aerobes - Pseudomonas
obligate anaerobes - Bacteroides, Clostridium methanogens
microaerophiles - Treponema pallidum
facultative anaerobes - Staphylococcus and E. coli
aerotolerant respiration - Lactobacillus (captures energy by fermentation)