This research presents the effect of hydrodynamic conditions at different rates of aeration (1.4, 1.8, and 2.3 vvm) and the geometry of two photobioreactors with internal lighting on lipid productivity and other parameters of Chlorella vulgaris. A two-step nitrogenreduction cultivation mode was applied for promoting lipid accumulation. The inoculum was cultivated initially at 90 mg L −1 N-NH 4 + , and at the end of the exponential phase, it was fed to 11 L photobioreactor at 20 mg L −1 of N-NH 4 +. The results showed that with similar aeration rates, the hydrodynamic regime in both photobioreactors was different. However, the increase in shear rate and agitation did not cause cell damage or photoinhibition. The maximum cell growth was 12 × 10 6 cells mL −1. The highest consumption of nitrogen was 19% and shear rates were of 120-340 s −1. The highest lipid productivity was reached in bubble column at 1.8 vvm with 0.650 mg•L −1 d −1 .

Kinetic rigidity of several polymers such as 2,6-bis(3-aminophenoxy)benzonitrile/4,4′oxydiphthalic anhydride (β-CN)APB/ODPA, poly[(2,2-dimethyl-1,3-dioxolan-4-yl)methyl acrylate)] (PACGA), and diglycidyl ether of bisphenol A (DEGEBA) was studied. Rigidity parameter D, Vogel’s temperature T0, and the activation energy Uα ( Tg) for the glass transition were evaluated through Vogel’s model along with relaxation data using “nonlinear” regression of Arrhenius function. The existence of certain functional groups within the structure, such as the aromatic rings, gives high level of kinetic rigidity to the structure as is the case of (β-CN)APB/ODPA and DEGEBA, while the aliphatic groups confer flexibility, as in PACGA.