No abstract

Progeny of 28 wild populations of Cordyline australis (cabbage tree, ti kouka) from a 12° latitudinal range in New Zealand grown under uniform garden conditions at Mt Albert, Auckland (36°53 S, 174°43 E), Lincoln, Canterbury (43°38 S, 172°29 E), and Invermay, Otago (45°51 S, 170°23 E), differed in the number of years they took to flower for the first time (years to first flowering, YFF) and in the date their flowers first opened each season (first flowering date, FFD). At Auckland population YFF was unrelated to latitude of origin, but at Lincoln and, especially, Invermay, there was a well-defined increase

The insecticidal crystal protein (ICP) synthesized at the onset of sporulation by Bacillus thuringiensis var. galleriae (Btg) is lethal against specific pests. Attempts were made to enhance the synthesis of biomass and ICP by Btg employing process optimization strategies. The process optimization was carried out with residual glucose concentration control in a bench scale bioreactor. A fuzzy logic-based feedback control system for maintaining the residual glucose concentration at a constant level during cultivation was developed in LabVIEW. This control system indicated the possibilities in providing a balanced substrate flux during cultivation. The identified optimum level of 2.72 g/l in residual glucose concentration was maintained by fed-batch cultivation with glucose and yeast extract fed at equal concentration with the above control system. High cell density of 16.0 g/l with specific growth rate of 0.69 h )1 was obtained during the cultivation. The balanced flux of substrate during cultivation has resulted in the enhanced synthesis of biomass and ICP. This optimized process could be commercially exploited by comparing the fluxes of basal compounds in different media sources used in fermentation.

The competition between the biodegradable polyhydroxyalkanoates (PHA) and petrochemical plastics could be in terms of cost of production. Also, the impact of PHA on the preservation of the environment has been established in detail. Eorts in the direction of obtaining cheaper raw materials could reduce the cost of production of PHA. Therefore, an experimental design-based medium optimization was carried out for the production of poly-bhydroxybutyrate (PHB) by Azotobacter beijerinckii in shake¯asks. Previous reports have not indicated the application of corn-steep liquor (CSL) as the nitrogen source. Thus attempts were made for the production of PHB using CSL and molasses as the carbon source. It was observed that the combination of molasses and CSL could be used in its production. Analysis of the experimental data has shown the optimum concentration to be 65.4 g/l of molasses and 13.2 g/l of CSL. Also, untreated molasses resulted in a higher yield in comparison with potassiumferrocyanide-treated molasses, indicating the contribution of unidenti®ed components favouring the growth and yield of PHB by Azotobacter beijerinckii.