Rita Kumar

Application of immobilized mixed bacterial culture for the degradation of phenol present in oil refinery effluent

Abstract Free and calcium alginate entrapped cells of four microorganisms namely Pseudomonas aeruginosa, Pseudomonas fluorescens, Serratia sp., and Yersiniasp, have been examined for degradation of phenol, present in oil refinery effluent by observing growth and tolerance capacity against toxic effects of phenol. The study of tolerance capacity of all the four microorganisms for different sublethal concentrations have shown that phenol concentrations above 200 mg/l was toxic to Pseudomonas fluorescens, while other three microorganisms tolerated phenol upto 400 mg/l. These four microorganisms were mixed for the formulation of microbial consortia and further used for the biodegradation of phenol present in oil refinery effluent. At bacteriostatic concentrations of phenol, toxicity effect has been found to be significantly lower in the case of immobilized bacteria in comparison to free cells. The immobilized microorganisms have been found to degrade 100% of phenol in 96 hrs., while the free cells degraded 80...

Biological Approach for the Treatment of Pulp and Paper Industry Effluent in Sequence Batch Reactor

Pulp and paper industrial effluent is rich in recalcitrant compounds and causes pollution. For the treatment of such compounds activated sludge process is frequently used in which F/M ratio is kept low. This treatment results in effective biochemical oxygen demand removal but other waste water parameters are not reduced effectively due to lack of dissolve oxygen. In the present study sequential batch reactor was used for the removal of pollutants from the waste water of pulp and paper mill by using bacterial consortium (Klebsiella sp., Alcaligens sp. and Cronobacter sp.). The aim of present research is to identify the influences of F/M ratio and dissolved oxygen concentration on the microorganism’s growth and pollutant removal. The process of bioremediation was optimized by Taguchi approach. Bioremediation experiment resulted in reduction of chemical and biochemical oxygen demand up to 72.3% and 91.1%, respectively. A significant reduction in colour (55%), adsorbable organic halides (45.4%), total dissolve solids (22%) and total suspended solids (86.7%) was also observed within 14hrs while, the sludge volume index was 52. The wastewater after the treatment process meets the standard given by regulatory agencies and can be discharged into the environment without any risks.

Biodegradation of sewage wastewater using autochthonous bacteria.

The performance of isolated designed consortia comprising Bacillus pumilus, Brevibacterium sp, and Pseudomonas aeruginosa for the treatment of sewage wastewater in terms of reduction in COD (chemical oxygen demand), BOD (biochemical oxygen demand) MLSS (mixed liquor suspended solids), and TSS (total suspended solids) was studied. Different parameters were optimized (inoculum size, agitation, and temperature) to achieve effective results in less period of time. The results obtained indicated that consortium in the ratio of 1u2009:u20092 (effluent : biomass) at 200u2009rpm, 35°C is capable of effectively reducing the pollutional load of the sewage wastewaters, in terms of COD, BOD, TSS, and MLSS within the desired discharge limits, that is, 32u2009mg/L, 8u2009mg/L, 162u2009mg/L, and 190u2009mg/L. The use of such specific consortia can overcome the inefficiencies of the conventional biological treatment facilities currently operational in sewage treatment plants.

Bioremediation of Agro-Based Pulp Mill Effluent by Microbial Consortium Comprising Autochthonous Bacteria

Small-scale agro-based pulp and paper mills are characterized as highly polluting industries. These mills use Kraft pulping process for paper manufacturing due to which toxic lignified chemicals are released into the environment. Lack of infrastructure, technical manpower, and research and development facilities restricts these mills to recover these chemicals. Therefore, the chemical oxygen demand (COD) of the emanating stream is quite high. For solving the above problem, four bacteria were isolated from the premises of agro-based pulp and paper mill which were identified as species of Pseudomonas, Bacillus, Pannonibacter, and Ochrobacterum. These bacteria were found capable of reducing COD up to 85%–86.5% in case of back water and 65-66% in case of back wateru2009:u2009black liquor (60u2009:u200940), respectively, after acclimatization under optimized conditions (pHu20096.8, temperature 35°C, and shaking 200u2009rpm) when the wastewater was supplemented with nitrogen and phosphorus as trace elements.

Validation of the use of microbial consortium as standard seeding material in BOD determination

An attempt is made to validate the use of a microbial consortium in BOD analysis. A uniform dehydrated microbial consortium, `BODSEED, has been used as a seeding material in BOD analysis of synthetic and other industrial effluents. Statistical analysis of the obtained BOD values shows that conventional seeding material such as sewage can be replaced by `BODSEED.

Usefulness of Organic Acid Produced by Exiguobacterium sp. 12/1 on Neutralization of Alkaline Wastewater

The aim of this study was to investigate the role of organic acids produced by Exiguobacterium sp. strain 12/1 (DSM 21148) in neutralization of alkaline wastewater emanated from beverage industry. This bacterium is known to be able to grow in medium of pH as high as pH 12.0 and to neutralize alkaline industrial wastewater from pH 12.0 to pH 7.5. The initial investigation on the type of functional groups present in medium, carried out using FT-IR spectroscopy, revealed the presence of peaks corresponding to carbonyl group and hydroxyl group, suggesting the release of carboxylic acid or related metabolic product(s). The identification of specific carboxylic group, carried out using RP-HPLC, revealed the presence of a single peak in the culture supernatant with retention time most similar to formic acid. The concentration of acid produced on different carbon sources was studied as a function of time. Although acid was present in same final concentration, the rate of acid production was highest in case of medium supplemented with sucrose followed by fructose and glucose. The knowledge of metabolic products of the bacterium can be considered as a first step towards realization of its potential for large-scale bioremediation of alkaline wastewater from beverage industry.

Validation of computationally predicted substrates for laccase

Present study reports the validation (oxidation) of computationally predicted oxidation of xenobiotic contaminants by commercially available pure laccase from Trametes versicolor. Selected contaminants were predicted as potential targets for laccase oxidation by using in-silico docking tool. The oxidation by laccase was measured by change in absorbance at specific λ max of each compound. Sinapic acid and tyrosine were taken as positive and negative controls, respectively. Oxidation was observed in m-chlorophenol, 2,4 di-chlorophenol, 2,4,6 tri-chlorophenol, captan, atrazine and thiodicarb, except malathion, which showed no activity. It could be speculated that the predicted substrates showing oxidation shared homology at structural and chemical level with positive control compounds. In case of malathion, structural non-homology with sinapic acid could be attributed to its inactivity towards laccase that required further structural analysis. Thus, a remediation tool proposing an advanced remediation approach combining the application of theoretical in-silico method and subsequent experimental validation using pure laccase could be proposed. As number and type of xenobiotics increase, the unfeasibility to screen them experimentally for bioremediation also rise. This approach would be useful to reduce the time and cost required in other screening methods.

ExtremeDB: A Unified Web Repository of Extremophilic Archaea and Bacteria

Extremophiles are the microorganisms which can survive under extreme conditions of temperature, pressure, pH, salinity etc. They have gained much attention for their potential role in biotechnological and industrial applications. The large amount of experimental data in the literature is so diverse, that it becomes difficult and time consuming for the researcher to implement it in various areas of research. Therefore, a systematic arrangement of data and redirection in a similar fashion through web interface can assist researchers in analyzing the data as per their requirement. ExtremeDB is a freely available web based relational database which integrates general characteristics, genome-proteome information, industrial applications and recent scientific investigations of the seven major groups of 865 extremophillic microorganisms. The search options are user friendly and analyses tools such as Compare and Extreme BLAST have been incorporated for comparative analysis of two or more extremophiles and determining the sequence similarity of a given protein/nucleotide in relation to other extremophiles respectively. The effort put forth herein in the form of database, would open up new avenues on the potential utility of extremophiles in applied research. ExtremeDB is freely accessible via http://extrem.igib.res.in.

Application of Defined Co-Immobilized Microbial Consortium as a Ready-to-Use Seed Inoculum in Bod Analysis

A number of microorganisms were isolated from sewage. Biochemical Oxygen Demand (BOD-5 day) analysis was carried out by individual pure cultures. The cultures giving higher or equal BOD values as compared to reference GGA solution were selected for the formulation of a defined mixed microbial consortium. This microbial consortium was co-immobilized on calcium-alginate beads. Four synthetic and six industrial samples were tested for BOD by using immobilized beads as well as sewage as source of seeding materials. BOD values obtained with beads for all the synthetic as well as industrial samples were fairly comparable with those obtained with sewage. Reusability of prepared microbial beads was also checked with different synthetic and industrial samples and was compared with reference GGA solution. The same microbial beads can be reused three times for different BOD-5 day estimations. It is recommended that immobilized microbial beads can be used as a ready-to-use seeding material for BOD analysis.

Restructuring BOD:COD Ratio of Dairy Milk Industrial Wastewaters in BOD Analysis by Formulating a Specific Microbial Seed

BOD (Biochemical oxygen demand) is the pollution index of any water sample. One of the main factors influencing the estimation of BOD is the nature of microorganisms used as seeding material. In order to meet the variation in wastewater characteristics, one has to be specific in choosing the biological component that is the seeding material. The present study deals with the estimation of BOD of dairy wastewater using a specific microbial consortium and compares of the results with seeding material (BODSEED). Bacterial strains were isolated from 5 different sources and were screened by the conventional BOD method. The selected microbial seed comprises of Enterobacter sp., Pseudomonas sp. BODu2009:u2009COD (Chemical oxygen demand) ratio using the formulated seed comes in the range of 0.7-0.8 whereas that using BODSEED comes in the ratio of 0.5-0.6. The ultimate BOD (UBOD) was also performed by exceeding the 3-day dilution BOD test. After 90 days, it has been observed that the ratio of BODu2009:u2009COD increased in case of selected consortium 7 up to 0.91 in comparison to 0.74 by BODSEED. The results were analyzed statistically by t-test and it was observed that selected consortium was more significant than the BODSEED.