Table 1.

The features of 3 different types of bacterial predators

Current predator type	Redefined predator type	Prey dependent/independent	Metabolic pathway deficiencies	Pure-culture cultivable	Storing nutrients as polymers	Predation strategy	Predation specificity
Obligate	Obligate	Completely prey-dependent	High	Extremely difficult	None	Contact-dependent	Gram-negative
Bradymonabacteria	Facultative	Facultatively prey-dependent	High	Difficult	Polyhydroxyalkanoates, polyphosphate, and alkanes	Contact-dependent	Gram-negative and Gram-positive
Facultative	Opportunistic	Prey-independent	Low	Normal	Polyphosphatea	Mostly contact-independent	Gram-negative and Gram-positive

^aA polyphosphate accumulation pathway was found in genomes but not determined by experiments