CDM	cell dry mass (g L−1)
C(t)	cumulative octanoic acid uptake as a function of time (g L−1)
N(t)	cumulative (NH4)2SO4 uptake as a function of time (g L−1)
Qv	overall volumetric productivity of PHA (g L−1 h−1)
Qs	specific productivity or PHA synthesis rate (g g Xr−1 h−1)
XPHA	PHA biomass (g)
Xr	non-PHA (residual) cell mass (g)
Xt	total biomass (g)
YPHA/S	yield coefficient of PHA per unit carbon substrate consumed (g g−1 or C-mol C-mol−1)
YXr/N	yield coefficient of non-PHA cell mass per unit ammonium consumed (g g−1 or mol mol−1)
YXr/S	yield coefficient of non-PHA cell mass per unit carbon substrate consumed (g g−1 or C-mol C-mol−1)
YX/S	yield coefficient of total biomass per unit carbon substrate consumed (g g−1 or mol mol−1)
μavg/Xr	average specific growth rate over a defined period (h−1, calculated using increases in Xr)
%PHA	intracellular PHA content (% of CDM)
[ ]	concentration braces (g L−1 or mg L−1)