Effect of ph and salinity on growth performance of cyanobacterium hapalosiphon welwitschii

Harsh Manchanda

Salinity and pH tolerance of heterocystous, branched cyanobacterium Hapalosiphon welwitschii, isolated from semi-arid wasteland was studied in response to salinity levels ranging from EC 5 to 15 ds/m at pH 7.5 (neutral) and pH 8.5 (alkaline). Growth performance was studied in terms of absorbance, biomass, concentration of photosynthetic pigments like chlorophyll, carotenoids and phycobilins. A decrease in all these parameters was observed with increasing salinity, indicating that this may be regarded as halotolerant cyanobacterium in which growth was maximum in control (EC 0.2 ds / m) but it sustained well at higher salinity levels although with a reduced growth rate. When pH of medium was increased to 8.5 (alkaline), overall growth pattern did not change but the relative growth was more in alkaline conditions as compared to that at pH 7.5, indicating that this strain has the potential to be used as biofertilizer in saline – alkaline soils.

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DOI: http://dx.doi.org/10.24327/ijcar.2017.8163.1302