Bioreactor culture of heterotrophic sandalwood (Santalum album L.) cell suspensions utilizing a cell-lift impeller.

Growth and phenolic production by two heterotrophic suspension cultures (SW-1 and SW-2) of sandalwood cultivated in a 2.5 L bioreactor were investigated. Cultures of SW-1 cell suspensions resulted in a maximum phenolic content of 32.5 mg L(-1) compared to 12.5 mg L(-1) produced by SW-2 cell suspensions. Fresh weight doubling time (Td) was 5.8 days and the specific growth rate (µ) was 0.12 d(-1) during exponential growth for both cell lines. The pH of the culture medium decreased from 5.5 to 3.5 during the exponential growth phase of SW-1 and SW-2 cell suspensions. The dissolved oxygen content also dropped steadily during culture and remained at 40% throughout exponential growth phase. These results should provide a basis for developing sandalwood cell cultures for bioproduction of useful compounds.

Culture of photomixotrophic soybean and pine in a modified fermentor using a novel impeller.

Photomixotrophic suspensions of Glycine max (soybean) and Pinus elliottii (slash pine) have been successfully cultured in a hybrid stirred tank photobioreactor using a novel cell-lift impeller. A cell-lift impeller exhibited cell viabilities over 90% and an average cell aggregate size of 1.0 mm or less. Flat-bladed turbines produced equivalent biomass to the cell-lift impeller, but cell viability was reduced (85%) and cell aggregate size increased (3-5 mm diameter). Maximum fresh weights of 82 g L(-1) (soybean) and 52 g L(-1) (slash pine) were achieved in 15 days using continuous lighting (90-100 microE m(-2) s(-1)) and supplemental 2% CO(2) inlet gas. Maximum biomass was achieved using an impeller speed of 60 rpm with air-flow rate of 0.2 vvm for the cell-lift impeller and the pair of flat bladed turbines. The lag and early exponential phases were characterized by (1) rapid hydrolysis of sucrose followed by preferential use of glucose and (2) a reduction in chlorophyll levels. Carbon dioxide (2%-5%) was an essential nutrient for photomixotrophic cell culture in the bioreactors.

Protein synthesis in slash pine callus cultures exposed to water stress.

Effects of water stress on protein synthesis were investigated in heterotrophic callus cultures derived from slash pine (Pinus elliottii Engelm.) cotyledon explants. Cultures were transferred to medium containing 0-15% mannitol to provide water potentials between -0.4 and -2.5 MPa. Beginning between 0 and 22 h after transfer to the new medium, cultures were incubated for 2 h with (35)S-methionine. Both the uptake of label and the incorporation of label into protein decreased with decreasing medium water potential. Incorporation, however, was reduced to a greater extent than uptake suggesting that the reduced incorporation was at least partly the result of reduced protein synthesis. Separation of labeled proteins by one-dimensional SDS-polyacrylamide gel electrophoresis and visualization by fluorography revealed the induction of two new protein bands after incubation at -1.8 MPa for 24 h. Induction of new proteins was not observed at other water potentials or after shorter incubation times. Protein bands from cultures incubated at -1.8 MPa for 24 h and then transferred for 24 h to mannitol-free medium (-0.4 MPa) were comparable to those from control cultures maintained on mannitol-free medium throughout.