Reliable determination of the growth and hydrogen production parameters of the photosynthetic bacterium Rhodobacter capsulatus in fed batch culture using a combination of the Gompertz function and the Luedeking-Piret model

Abstract

In this study, experimental results of hydrogen producing process based on anaerobic photosynthesis using the purple non-sulfur bacterium Rhodobacter capsulatus are scrutinized. The bacterial culture was carried out in a photo-bioreactor operated in a quasi-continuous mode, using lactate as a carbon source. The method is based on the continuous stirred tank reactors (CSTR) technique to access kinetic parameters. The dynamic evolution of hydrogen production as a function of time was accurately simulated using Luedeking-Piret model and the growth of R. capsulatus was computed using Gompertz model. The combination of both models was successfully applied to determine the relevant parameters (λ, μ max , α and β) for two R. capsulatus strains studied: the wild-type strain B10 and the H 2 over-producing mutant IR3. The mathematical description indicates that the photofermentation is more promising than dark fermentation for the conversion of organic substrates into biogas.

Conversion of Sweet Whey to Bioethanol: A Bioremediation Alternative for Dairy Industry

“…The substrate consumption rate (-rs) increased with the presence of L-Phe because the assimilation of lactose in K. marxianus could have occurred through the lactose permease encoded by the LAC12 gene and hydrolyzed by intracellular β-galactosidase encoded by the LAC4 gene; catabolized by the Leloir pathway through an enzymatic reaction to produce BioEtOH [10,35]. Concerning the substrate consumption rates (-rs) obtained with Monod's equation for F3 and F6 of 1.26 and 1.27 g L −1 h −1 (R2) 0.99, they are higher than those obtained by Hadiyanto et al, [33], Ozmihci et al, [36] and Lukondeh et al, [37] with values of 0.32, 0.37, and 0.16 g g −1 , respectively, in similar lactose concentrations (48 g L −1 ) at 30 • C. The results of -rs for formulations F3 and F6 depend on the operation conditions, the nature of the substrate, the addition of precursors, and the used microorganism [30]. Regarding the product formation rate (rp), the simultaneous addition of ammonium sulfate and L-Phe (F4 to F6) showed a significant decrease in rp compared to raw sweet whey (F1).…”

“…Experimental data were independently fitted to the Gompertz equation, using nonlinear regression according to Deseure et al [30], with the Marquardt algorithm and the following equation:…”

A machine learning‐based approach for improving plasmid DNA production in Escherichia coli fed‐batch fermentations

“…To investigate process dynamics of biomass (X), plasmid yield (P), and substrate (S), kinetic models such as logistic and Luedeking-Piret kinetics were established based on the acquired database. [27][28][29] 2.5.1…”