AU	Arbitrary units
CDW	Cell dry weight
CFV	Crossflow velocity
F	Flow rate
LA	Lactic acid
μ	Specific growth rate
M	Mass of biomass represented by offline measurements
MBR	Membrane bioreactor
MWCO	Molecular weight cutoff
MO	Microorganism
N	Mass of biomass represented by online measurements
NIR	Near infrared
ODx	Optical density at λ = x nm
P	Pressure
PLA	Polylactic acid
Q	Productivity of lactic acid
RO	Reverse osmosis
t	Time
T	Temperature
TMP	Transmembrane pressure