Comparison of two membrane – photobioreactors, with free or immobilized cells, for the production of pigments by a marine diatom

Abstract

The present study concerns the value enhancement of the microalga Haslea ostrearia. This marine diatom bears the peculiarity of synthesizing and secreting in the culture medium a blue-green pigment named`m arennine''. Anticancer research, cosmetics and aquaculture are the ®elds concerned with the utilizations of this hydrosoluble pigment. The aim of the study is to compare the pigment productivity obtained with two types of photobioreactors. In the ®rst process, cells are free and recycled in a bioreactor combined with a membrane ultra®ltration equipment (external loop). In the second system, cells are entrapped in a tubular agar gel layer in a photobioreactor of original design. The in¯uence of nitrate concentration and renewal rate is examined. Experiments, conducted on long term periods (up to 40 d) without any external contamination, revealed that marennine productivities of more than 5±7 mg 10 9 cell )1 d )1 can be reached with both bioreactors. The advantages and drawbacks of each process design are also discussed.

Immersed hollow fibres microfiltration (MF) for removing undesirable micro-algae and protecting semi-closed aquaculture basins

“…Many studies relate to the separation of the micro-algae with various membrane processes [8][9][10][11][12][13][14][15][16] but more especially, a previous study [17] investigated immersed membranes for seawater pre-treatment dedicated to total removal of undesirable micro-algae. In our previous study [17], polysulfone immersed hollow fibers microfiltration (MF) and ultrafiltration (UF) membranes were compared.…”

Biotechnological hydrogen production by photosynthesis

“…The system outperformed conventional plate-type reactors, yielding hydrogen production rates of 2 L×m −2 ×h −1 . Rossignol et al [49] compared two completely different applications of membranes in photobioreactor systems. The first system they tested was a free-cell bioreactor, in which the cell culture was recirculated between a glass tubular reactor and a membrane-based ultrafiltration module.…”

“…(A) Multilayered plate reactor . (B) Immobilized cells reactor (ICB) . (C) Stack of flat monoliths .…”

Growth Kinetics, Light Dynamics, and Lipid Production in Microalgae from Sugar-Mill Ponds

“…Collecting empirical data on these parameters is necessary for modeling, defining optimum conditions, and understanding production under various growth conditions. The design and operational factors that influence these parameters include depth of culture, mixing rate (cell light/dark cycling frequency), dilution rate, nutrients, temperature, salinity, and distance of light source from the culture surface in the case of artificially lighted systems 10,27,29,30,[38][39][40][41][42] . Numerical models, such as those developed by Benson et al 7,37,43 and Lohrey and Kochergin 16 are needed to simulate and optimize microalgal production in sugar-mill wastewaters.…”