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The baculovirus-insect cell expression system is widely used in producing recombinant proteins. This review is focused on the use of this expression system in developing bioprocesses for producing proteins of interest. The issues addressed include: the baculovirus biology and genetic manipulation to improve protein expression and quality; the suppression of proteolysis associated with the viral enzymes; the engineering of the insect cell lines for improved capability in glycosylation and folding of the expressed proteins; the impact of baculovirus on the host cell and its implications for protein production; the effects of the growth medium on metabolism of the host cell; the bioreactors and the associated operational aspects; and downstream processing of the product. All these factors strongly affect the production of recombinant proteins. The current state of knowledge is reviewed.

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ubble columns and airlift photobioreactors can be useful for culturing phototrophic organisms requiring light as a nutrient. Light a®ailability in bubble columns and airlift ( de®ices is influenced by aeration rate, gas holdup, and the liquid ®elocity mixing and ) turbulence . The photosynthetically generated oxygen also needs to be remo®ed, as ex-cessi®e dissol®ed oxygen suppresses photosynthesis. Oxygen remo®al capacity is go®erned by the magnitude of the o®erall gas ᎐ liquid mass-transfer coefficient, k a . This work L L characterizes the rele®ant hydrodynamic and mass-transfer parameters in three airagitated reactors: bubble column, split-cylinder airlift de®ice and concentric draft-tube sparged airlift ®essel. The reactors are then e®aluated for culture of the microalga Phaeodactylum tricornutum. All reactors were about 0.06 m 3 in working ®olume, and the working aspect ratio was about 10. Data were obtained in tap water for a base-line comparison and in Mediterranean seawater, as a potential medium for algal culture. A theoretical relationship was de®eloped and pro®ed between k a and the aeration rate. L L In addition, a method based on mechanistic relationships was pro®ed for predicting the liquid circulation ®elocity and k a in airlift reactors. Existing correlations applied sat-L L isfactorily to gas holdup and k a data obtained in the bubble column. Aqueous solu-L L ( ) tion of sodium chloride 0.15 M closely resembled seawater in terms of its hydrodynamics and oxygen transfer beha®ior. Under the conditions tested, all three reactors attained a biomass concentration of about 4 kg ؒ m y 3 after ; 260 h. The mean maximum specific growth rate was 0.022 h y 1 in all cases at a power input of 109 W ؒ m y 3 .

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