BIOSCIENCES BIOTECHNOLOGY RESEARCH ASIA, September 2017. Vol. 14(3), p. 1129-1134 * To whom all correspondence should be addressed. E-mail: snehabiotech@yahoo.com Study of Water Quality and Biochemical Characterization of Bacterial Isolates from Water Samples of Ponnagi Area in Krishna District Jyothi Kshatri 1 *, C.V. Rao 1 and Vijaya Saradhi Settaluri 2 1 Sneha Biotech, Chukkapalli Vari Street, Labbipet,Vijayawada-520010, Andhra Pradesh, India. 2 Associate Professor, Department of Biotechnology, K L University, Vaddeswaram-522502, Andhra Pradesh, India. http://dx.doi.org/10.13005/bbra/2551 (Received: 31 July 2017; accepted: 09 August 2017) Aquaculture also known as fish farming is one of the methods for breeding rearing and harvesting of freshwater and marine species of fish and shellfish, in ponds, rivers, lakes and oceans. In this article an attempt has been put forth to study and apply techniques that could help in improving the water quality in aquaculture ponds and to further understand the role played by enzymes and probiotics by means of bio remedial procedures and protocols. Aquaculture productivity needs to be improved to cater the ever-increasing demand, no doubt, but simultaneously a proactive role for environment protection is required. The gathering of organic wastes worsens the water quality and reduces the level of dissolved oxygen in the fish aquaculture ponds. This further increases the formation of toxic metabolites such as ammonia (NH 3 ), nitrite (NO 2 - ) and hydrogen sulphide (H 2 S). Hence, NH 4 + or NO 3 - removal processes (nitrification and denitrification) become essential for the pond water quality. This can be carried out by applying different types of nitrifying and denitrifying bacteria such as Nitrosomonas, Nitrobacter and Alcaligenes. In the present investigation, 2 earthen ponds were selected from Ponnagi near Eluru in Krishna district, Andhra Pradesh, India. One pond (Pond A) was treated with probiotics having Nitrosomonas, Nitrobacter and Alcaligenes sps. And the other pond (Pond B) was kept as control. During the culture period, the water samples were collected from probiotics treated and control ponds for analysis of water quality parameters. The current study is aimed to focus on the changes in water quality and biochemical characterization of bacterial isolates from water samples of Ponnagi area in probiotic treated ponds and to compare the results with ponds not treated with probiotics. Keywords: Probiotics, Microorganisms, quality, characterization, ponds, Aquaculture. At present the fastest growing food production industry in the world is Aquaculture (Josupieh.H; et al , 2000). The aquaculture market has been growing at impressive rates in recent years, which is expected with our growing population. Supplying fish sustainably is a challenge as ponds and hatcheries are easily contaminated with biomass, shell, faecal matter and other pollutants. These contaminants reduce the levels of O2 and produce ammonia and other gases that are harmful to species and lead to disease. Excessive and irresponsible harvesting can create large scale disease outbreaks, such as early mortality syndrome seen in recent years in some parts of the world. The culture environment becomes unstable, with the increase in fish biomass, and is highly susceptible to changes in water quality conditions. Due to such changes there may be a direct effect on the health of the fish, and for