Why and how membrane bioreactors with unsteady filtration conditions can improve the efficiency of biological processes.
A membrane bioreactor (MBR), an association of a bioreactor with a crossflow filtration unit, enables continuous processes with total cell retention within the reactor to be realized. Provided that high dilution rates can be applied and that inhibition processes are avoided, very high biomass concentrations can be reached, thereby improving the volumetric productivities. These membrane bioreactors have been successfully applied to various microbial bioconversion, such as alcoholic fermentation, solvents, organic acid production, starters, and wastewater treatment. On the basis of the biological reaction characteristics and bibliographic results, the potentialities and bottlenecks of this methodology are discussed. Depending on the application, it is shown how the performance of the membrane bioreactor can be enhanced by acting either on the biological reaction achievement, by controlling the balance between cell growth and death, or on the dilution rate, by increasing the permeate flux through the filtration unit. This discussion is based on results obtained in specific biological treatments applied to polluted liquid and gas.
Daubert
Isabelle
I
Laboratoire Biotechnologie-Bioprocédés, Institut National des Sciences Appliquées, UMR INSA CNRS 5504, UMR INSA INRA 792, Tououse, France.
Mercier-Bonin
Muriel
M
Maranges
Claude
C
Goma
Gérard
G
Fonade
Christian
C
Lafforgue
Christine
C
D019149:Bioreactors; D002175:Candida / Q000302:isolation & purification; D005285:Fermentation; D005374:Filtration; D008567:Membranes, Artificial; D010100:Oxygen / Q000378:metabolism
D008567:Membranes, Artificial; D010100:Oxygen