ISOLATION AND IDENTIFICATION OF POTENTIAL INDIGENOUS BACTERIA USEFUL FOR BIOREMEDIATION OF BREWERY EFFLUENTS

Abstract

The brewery industry consumes daily a large volume of water and chemicals and generates a high amount of nutrient-rich wastewater. The discharge of this wastewater into the environment without proper treatment causes serious and prolonged ill consequences on the ecosystem. Thus, the objectives of this study were to assess the physicochemical characteristics of Harar Brewery effluent; to isolate, identify and determine the efficiency of the indigenous bacteria in removing or reducing hazardous environmental components from the effluent. To this end, brewery effluent and effluent contaminated soil samples were randomly collected from Harar Brewery Industry and used for isolation of the indigenous bacterial species. Accordingly, a total of 16 different bacterial colonies were isolated from the brewery effluent and effluent-contaminated soil. Of the 16, nine were selected to test their abilities in reducing pollutants. These isolates were subjected to identification procedures using their morphological and biochemical characteristics. Attempts were also made to further characterize four of the best isolates (WS3, WS5, WS9, and SS4) at a molecular level. For molecular characterization, genomic DNA was extracted from each isolate using a genomic DNA kit. From the resulting genomic DNA, 16S rRNA fragments were amplified by PCR using bacterial universal primers. The sequence analysis of the fragments revealed that the four isolates were Bacillus subtilis(WS3), Bacillus pumilus (SS4), Bacillus sp (WS9), and Lysin bacillus sphaericus (WS5). After identification, the bacterial species/isolate were analyzed for their inherent effectiveness in removing the pollutants of brewery effluents based on physicochemical parameters such as pH, EC, Temperature, TSS, TDS, TS, COD, BOD, TN, TP, and Turbidity. The results showed that before treatmet the mean values of these parameters for the brewery effluents were 7.2±0.7, 3.3±0.2 mS/cm, 19.5±0.50C, 600±10 mg/L, 4700±5.0 mg/L, 5300±9.0 mg/L, 573.20±26, 480±20, 15±0.7, 22±0.6 and 359±3.0 NTU, respectively. After 12 days of treatment, however, the values for TSS, TDS, TS, COD, BOD, TP, TN and Turbidity were reduced to 380 mg/L to 150.81 mg/L (36.67% to 74.86%); 2858.83 mg/L to 1617.08 mg/ L(39.17% to 65.59%); 3192.91 mg/L to 1748.79 mg/L(39.76% to 67%); 249.11 mg/L to 116.43 mg/L(56.54% to 79.69%); 313.12 mg/L to 182.01 mg/L(34.78% to 62.08%); 6.58 mg/L to 3.24 mg/L(56.14% to 78.40%);13.43mg/L to 5.75 mg/L(36.94% to 73.85%) and 266.41NTU to 96.46 NTU(25.79% to73.13%), respectively. The current findings gives insight into the use of potential bacterial isolates in a green and environmentally sustainable approach that offers a promising alternative for wastewater treatment, as well as the development of this experimental system into a large-scale working as alternative waste treatment.