Changes in the carbon metabolism in nitrophenol-grown cultures of Nostoc linckia and Scenedesmus bijugatus, isolated from rice soil

The response of photosynthetic metabolism of carbon towards nitrophenol treatment in cultures of Nostoc linckia and Scenedesmus bijugatus was assessed by examining the cellular contents and activities of the enzymes. The starch content and non-reducing sugars were significantly lower in nitrophenol-grown cultures. The alterations were marked in activities of the enzymes involved in starch metabolism. The enhancement in the activity of phosphorylase clearly supports the observed reduction in accumulation of both starch as well als non-reducing sugars. The decreased activities of fructose 1,6-biphosphatase and sucrose phosphate synthase, and the enhanced activity of invertase resulted in low level accumulation of non-reducing sugars. The observed high activity of acid phosphatase resulted in concomitant decrease in levels of starch.