Be around; proceed and turn air back for microorganisms (8)
I believe the answer is:
bacteria
'back for microorganisms' is the definition.
'bacteria' can be an answer for 'microorganisms' (I've seen this before). I'm not sure about the 'back for' bit.
'be around proceed and turn air' is the wordplay.
'around' is an insertion indicator.
'proceed' becomes 'act' (I am not sure about this - if you are sure you should believe this answer much more).
'and' is a charade indicator (letters next to each other).
'turn' says the letters should be written backwards.
'air' reversed gives 'ria'.
'be' going around 'act' is 'bacte'.
'bacte'+'ria'='BACTERIA'
Can you help me to learn more?
(Other definitions for bacteria that I've seen before include "Microscopic organisms, may cause disease" , "Micro-organisms, often pathogens" , "Single-celled microorganisms" , "Single-cell organisms, can be good or bad for you" , "I eat crab (anag)" .)