Characteristic
Type 1
Type 2
Cell morphology
Short rods, usually occur singly; some cocci or ellipsoids
Crescent-shaped rods, rods, pear-shaped cells, sometimes occur in rosettes
G+C content of DNA (mol%)
49-60
62-67
Nitrogen fixation
No
Yes
RuMP pathway present
Yes
No
Serine pathway
No
Yes
Table 1:
Differential biochemical and physiological characteristics of type I and II methanotrophic bacteria [51].