Potential application of β-1, 3 glucanase from an environmental isolate of Pseudomonas aeruginosa MCCB 123 in fungal DNA extraction.

Pseudomonas aeruginosa MCCB 123 was grown in a synthetic medium for β-1,3 glucanase production. From the culture filtrate, β-1,3 glucanase was purified with a molecular mass of 45 kDa. The enzyme was a metallozyme as its β-1,3 glucanase activity got inhibited by the metal chelator EDTA. Optimum pH and temperature for β-1,3 glucanase activity on laminarin was found to be 7 and 50 °C respectively. The MCCB 123 β-1,3 glucanase was found to have good lytic action on a wide range of fungal isolates, and hence its application in fungal DNA extraction was evaluated. β-1,3 glucanase purified from the culture supernatant of P. aeruginosa MCCB 123 could be used for the extraction of fungal DNA without the addition of any other reagents generally used. Optimum pH and temperature of enzyme for fungal DNA extraction was found to be 7 and 65 °C respectively. This is the first report on β-1,3 glucanase employed in fungal DNA extraction.

Optimum growth requirements of nitrifying consortia developed from treated sewage.

The optimum growth requirements of two nitrifying consortia developed from treated sewage by enrichment technique were determined by a series of experiments. There was total inhibition of nitrification at above 2.75 g l(-1) NH4(+)- N and 2.5 g l(-1) NO2(-)-N and the ammonia oxidizing consortium preferred a pH at 8.5 and the nitrite oxidizing consortium a pH of 7.5 as the optima for nitrification. Optimum temperatures were between 20 degrees and 30 degrees C for both the groups. As the rate of airflow was increased from 1 to 7 l/min, the build-up of NO2(-)-N increased 10-fold and the consumption of NO2(-)-N increased by a factor of 28.8 implying that the ammonia oxidizing consortium in a bioreactor required three times more aeration than that for nitrite oxidizers for expressing their full nitrifying potential. These data directly contribute for developing a fermentation process for the mass production of nitrifiers as well as for designing bioreactors for nitrifying sewage.