Case Study on Biotechnology:
Detoxification of vinyl chloride to ethene coupled to growth of an anaerobic bacterium
An unusual, strictly anaerobic bacterium designated Dehalococcoides strain BAV1, was discovered that destroys dichloroethenes and vinyl chloride as part of its energy metabolism, generating environmentally benign products (biomass, ethene and inorganic chloride). This organism might be useful for cleaning contaminated subsurface environments and restoring drinking-water reservoirs.
One site that appears likely to benefit from in-place bioremediation with this bacterium is the Bachman Road residential area contaminated with PCE by a former dry cleaning operation in Oscoda, Mich.At this contaminated site, PCE penetrated the water table and contaminated drinking-water wells in the area. The contaminants also migrated through the groundwater into nearby Lake Huron, which attracts sunbathers and swimmers to its beaches and water. In 14-feet by 16-feet, 20-feet-deep test plots at the Bachman Road site, researchers compared a non-treated control section to two bioremediation approaches using BAV1, which already occurs at this site in low numbers. In another section, researchers injected a mixed culture containing high numbers of BAV1 along with nutrients. This technique resulted in complete dechlorination of PCE to ethene within six weeks.
(Source: www.nature.com)
Nature 424, 62-65 (3 July 2003)
Bacteria Metabolically Engineered for Enhanced Phytochelatin Production and Cadmium Accumulation
This study showed phytochelatins (PCs) with good binding affinities for a wide range of heavy metals were exploited to develop microbial sorbents for cadmium removal. PC synthase from Schizosaccharomyces pombe (SpPCS) was overexpressed in Escherichia coli, resulting in PC synthesis and 7.5-times-higher Cd accumulation. The coexpression of a variant -glutamylcysteine synthetase desensitized to feedback inhibition (GshI*) increased the supply of the PC precursor glutathione, resulting in further increases of 10- and 2-fold in PC production and Cd accumulation, respectively. A Cd transporter, MntA, was expressed with SpPCS and GshI* to improve Cd uptake, resulting in a further 1.5-fold increase in Cd accumulation. The level of Cd accumulation in this recombinant E. coli strain (31.6 µmol/g [dry weight] of cells) was more than 25-fold higher than that in the control strain.
(Source: Applied and Environmental Microbiology. 73(19) (2007): 6317-6320)
Novel pollutant-resistant methylotrophic bacteria for use in bioremediation
Thirty one novel methylotrophic bacterial strains were isolated from a range of soil and sediment sources (both pristine and polluted) under different enrichment regimes. They were characterised physiologically and classified by their 16S rRNA gene sequence. A great taxonomical and phenotypical variety was recovered. Some of the isolates display interesting features of resistance to heavy metals, arsenate or organic pollution and four can be considered real 'super-bugs' for their ability to withstand extremely high concentrations of a variety of pollutants. A description of the 31 strains is presented in this work.
(Source: www.scienedirect.com)
FEMS Microbiology Letters, Volume 234, Issue 1, 1 May 2004, Pages 75-80
Laboratory scale bioremediation of petroleum-contaminated soil by indigenous microorganisms and added Pseudomonas aeruginosa strain Spet
The bioremediation of petroleum-contaminated soil was investigated at laboratory scale, using three different approaches. The first approach comprised biostimulation of indigenous microorganisms. The second approach involved combination of biostimulation of indigenous microorganisms and bioaugmentation by inoculation with free cells of petroleum degrading Pseudomonas aeruginosa strain Spet. The third was a variation of the second, in which inoculation with encapsulated cells in starch and sodium alginate of P. aeruginosa strain Spet was applied. The bioremediation of the original hydrocarbon-contaminated soil (3.5% dry weight) and that of diluted with clean natural soil at 1:1 w/w were investigated. By providing sufficient moisture, nutrients and aeration by stirring in the original contaminated soil, total concentration of n-alkanes was reduced by 94% after 191 days of treatment and total concentration of 16 polycyclic aromatic compounds by 79%, while for the 1:1 diluted soils biodegradation reached 89% and 79%, respectively. The results showed that bioaugmentation with free or encapsulated P. aeruginosa cells and/or soil dilution had no significant effect on biodegradation.
(Source: www.scienedirect.com)
Bioresource Technology, In Press, 2010
Biodegradation of lubricating oil in wastewater with Zoogloea sp
This study showed to identify microbial strains that have a strong ability to biodegrade lubricating oil. No. 20 lubricating oil was used as the sole carbon source in an isolation medium to screen bacteria from sludge that had been contaminated with crude oil. Through both morphological and biochemical methods, the bacterial strain that had the highest biodegrading capacity was identified as Zoogloea sp. On the basis of these preliminary results, a biological contact oxidation method was employed to further assess the ability of the Zoogloea sp. strain to treat wastewater contaminated by No. 20 lubricating oil using three oxidation cabins and two hydraulic retaining times (HRT). Results showed that the concentration of No. 20 lubricating oil with a 12 h hydraulic retaining time and 16.5 L h?1 inflow rate was reduced by 99.3% in 15 d, and with a 6 h hydraulic retaining time and 33 L h?1 inflow rate it decreased by 98.6% in 12 d. The results from this study indicated that Zoogloea sp. had a strong potential to be utilized in biodegradation of lubricating oil.
(Source: www.scienedirect.com)
Pedosphere, Volume 16, Issue 4, August 2006, Pages 540-544
Biodegradation potential of pure and mixed bacterial cultures for removal of 4-nitroaniline from textile dye wastewater
Environmentally toxic aromatic amines including nitroanilines are commonly generated in dye contaminated wastewater in which azo dyes undergo degradation under anaerobic conditions. This study showed a process for biological treatment of 4-nitroaniline. Three bacteria identified as Acinetobacter sp., Citrobacter freundii and Klebsiella oxytoca were isolated from enrichment cultures of activated sludge on 4-nitroaniline, after which the isolates and the mixed culture were studied to determine optimal conditions for biodegradation. HPLC analyses showed the mixed culture was capable of complete removal of 100 ?mol/L of 4-nitroaniline within 72 h under aerobic conditions. There was an inverse linear relationship (R2 = 0.96) between the rate of degradation (V) and 4-nitraoaniline concentrations [S] over 100-1000 ?mol/L. The bacterial culture was also capable of decolorizing structurally different azo dyes (Acid Red-88, Reactive Black-5, Direct Red-81, and Disperse Orange-3) and also degraded nitrobenzene. Findings of this study showed that enrichment cultures from activated sludge can be effective for the removal of dyes and their toxic intermediates, and that treatment may best be accomplished using an anaerobic-aerobic process.
(Source: www.scienedirect.com)
Water Research, Volume 43, Issue 4, March 2009, Pages 1110-1116
Removal of pyridine and picoline by bacteria and fungus consortium
ITRC, Lucknow has developed microbial techniques for degradation of pyridine and picoline raffinate for safe disposal. The aerobic bacterial strain ITRC EM1 and ITRC EM2 were isolated and identified as Bacillus cereus (DQ435020) and Alcaligens faecalis (DQ435021). The bacterial consortia are capable to degrade pyridine from 20% pyridine raffinate up to 95.99 % within 7 days of incubation at temperature range 35-37OC after chemical pretreatment inpresence of 1% (w/v) glucose and 0.5% (w/v) peptone. All isomers of picoline (á,â and ă) were degraded from pyridine raffinate along with pyridine by isolated bacterial strain and Aspergillus niger separately upto 95.99% and 96.98% respectively. There was more than 80% toxicity reduction in pyridine raffinate after bacterial and fungal degradation. The study concluded that biological detoxification of pyridine raffinate is possible only after chemical pretreatment.
Degradation of Nitroaromatic compound by bacterial consortium
IIT, Kanpur has isolated and characterized pure bacterial strains for the degradation of few xenobiotic compounds and toxic organic compounds. Nitroaromatic compounds were degraded by bacterial strains NP-1 and NP-2, which were identified to be Pseudomonas aeruginosa and Serratia marsecens. A bacterial strain PNS-1 was isolated for 4- Aminobenzene degradation during the study and was characterized to be belonging to the genus, Agrobacterium. Dimethylformamide (DMF) was degraded by 16S rRNA gene, which belongs to Paracoccus strain. Pathways for their degradation have been identified. Although plasmids have been detected in two strains, their actual role in degradation of specific growth substrates is yet to be delineated.
Rotating Biological Contacter (RBC) enhance oil degradation
IIT, Bombay has isolated microorganisms degrading hydrocarbons in petroleum oil and in oily wastes in Rotating Biological Contacter (RBC). Specific means for enhancing adherence of oil degrading microorganisms to the rotating discs in the RBC was explored in a bench-scale RBC model and in a floor model.
An unique biofilter system efficiently removes waste gas containing dimethyl sulphide
At NEERI, Nagpur, potential bacterial cultures were isolated for deodorization of sulphurous compounds. The isolated cultures were characterized for colony morphology, biochemical and physiological characteristics and are under the process of identification. The isolated cultures have been used for treatment of waste gas containing dimethylsulphide in a biofilter system packed with wood chips and compost. The bench scale unit is under evaluation for optimization of process parameters viz Effective Bed Retention Time (EBRT), loading, moisture, pH of the medium, recovery after shock load etc.
Anaerobic Bioreactor effectively remove colour from molasses effluent
Sardar Patel University focussed on improvisation of existing anaerobic treatment technologies by introducing potential anaerobes, developing efficient bioreactors and exploring additional microbial treatments to remove color from molasses effluent.
Aerobic detoxification method of Cr (VI) by bacterial isolation
At IIT Chennai, a new bacterial strain Arthrobacter rombhi RE has been isolated. A continuos aerobic system was developed which was able to achieve 95% of Cr (VI) reduction (initial concentration: 25mg/L) and around 90% COD reduction (initial concentration: 2000mg/L and molasses as the carbon source) at a Hydraulic Retention Time (HRT) of 12hrs. Nolina recurvata (Palam flower), Ganoderma lucidum (wood rotting fungus) and few aquatic weeds have been extensively studied for biosorption potential. Various instrumental techniques have also been developed for biosorption of Cr (VI) and Cr (III).
Bioconversion of Agrowaste to Polyhydroxyalkanoates (PHA) by applying salt tolerant bacteria
Scientists at Agharkar Research Institute, Pune have isolated alkalophilic and salt tolerant bacteria from Lunar Lake, which are able to synthesize Polyhydroxyalkanoates (PHA). The process has been optimized for different parameters like temperature, pH, inoculum density and incubation period. FTIR (Fourier Transform Infrared Spectroscopy) and H NMR (Nuclear Magnetic Resonance) analysis confirmed the presence of copolymer hydroxybutyrate and hydroxyvalerate in 96:4 proportion. The organism could utilize agro waste like wheat bran for production of the polymer.
Nine potent terrestrial plant species used for phytoremediation of distillery waste
University of Rajasthan, Jaipur has identified the most tolerant plant species for the development of Ecotechnology for distillary waste treatment. 9 terrestrial (7 glycophytes and 4 halophytes) and 5 marshy species were studied in spent wash in different seasons under two types of irrigation practices at field capacity viz. surface and subsurface. Plant growth was quantified in terms ofdifferent seasons under two types of irrigation practices at field capacity viz. surface and subsurface.Plant growth was quantified in terms of biomass, chlorophyll and proline contents
Specific gene-chip was characterized for degradation of persistent pollutant
Industrial Toxicology Research Centre, Lucknow aims to detect the functional genes and study their expression levels in natural environments in a high throughput format such as a DNA microarray. They have developed 50-mer based oligonucleotide microarray based on most of 2,402 known genes involved in biodegradation and metal resistance. The oligos arrayed were specific to genes involved in biodegration of synthetic compounds like polyaromatic hydrocarbons (PAHs), monocylic aromatic compounds like BTEX, textile dyes, metal and nitro aromatic compounds and pesticides. This specific gene-chip is being validated with few organisms having genes for well-characterized degradative pathways.
Alcohol production from cellulosic waste
In an ongoing project on bioethanol production at Osmania University, Hyderabad, efficient cellulose producing microorganisms have been identified. Pentose utilizing fusant has been constructed by protoplast fusion between thermotolerant yeast and Candida utilis. Fusant strain has been sent to IMTECH, Chandigarh for molecular characterization. Cloning, expression and confirmation studies are in progress. Ethanol fermentation upto 20 litre level was carried out. Further optimization work is going on. Cyanobacterial strain, Phormidum sp. BDU-5 has also been used for degradation of different cellulosic wastes like P. julflora, L. camara and coir pith. By products released during degradation are being studied. Besides, phenolic compounds like 3, 4- dimethoxy cinnamic have been isolated and furher purification is being carried out by solvent extraction and column chromatography.
Microbial Treatment of Cassava Starch Factory Waste Water
Central Tuber Crops Research Institute (CTCRI), Thiruvananthapuram has standardised technology for degradation of starch factory waste water. Three microbial isolates from cassava processing wastewaters which were found to reduce cyanide by 81-84%, 50-59% and 71-83% respectively during an incubation period of 24-96 hours were successfully immobilized on various supports. The wastewater from cassava starch factories when treated anaerobically generated biogas at various stages of hydraulic retention time ( HRT ). The gas produced was in a range of 26 litres and 17 litres during HRT from 20 days to 1 day when the feed volume of waste water was increased from 20% to 100% and the volume of fresh cowdung slurry was reduced from 40% to nil. The anaerobically treated waste water was further aerated for 16 hours and the resultant BOD, COD and cyanide levels were brought to acceptable levels.
Paper and Pulp Mill Effluent Treatment
GB Pant University of Agriculture and Technology has developed a pilot scale technology 100 Litres for treatment of paper and pulp mill effluent.
Dye Industry Effluent Treatment
Rajasthan University, Jaipur has developed an efficient phytoremediation technology for degradation of reactive azodyes in waste water from textile dyeing industries. The technology has been demonstrated at the site of Shyam dyeing company in Sanganer. A common effluent treatment plant for treatment of waste from 3 units has been set up which has capacity to treat 35000 litre per day of textile wastewater.
Sardar Patel University, Anand has developed bench scale sequential anaerobic –aerobic treatment system consisting of anaerobic upflow film bioreactor and fluidized bed bioreactor for treatment of reactive dye industry effluent.
Oilzapper Technology for Bioremediation of Crude Oil Spills & Treatment of Oily Sludge
Oilzapper technology developed by TERI, New Delhi for crude oil spill treatment and oily sludge degradation has been demonstrated at a no. of refineries viz., Barauni Refinery , Bihar, Bharat Petroleum Corporation Ltd., Kandla Terminal , Gujarat, Bharat Petroleum Corporation Ltd.,Mumbai, Maharashtra, Digboi Refinery , Assam, Guwahati Refinery ,Assam, Hindustan Petroleum Corporation Ltd., Panipat ,Haryana and Visakhapatnam , Andhra Pradesh, Indian Oil Corporation Ltd., Kanpur , U.P and Rajkot Terminal, Gujarat, Mathura Refinery ,Mathura , Uttar Pradesh, Oil India Ltd., Duliajan , Assam, Oil & Natural Gas Corporation Ltd., Jorhat , Assam and Reliance Refinery, Jamnagar , Gujarat and more than 11,610 tonnes of sludge has been treated using oilzapper. The technology has been transferred to M/s Sriram Biotech Ltd., Hyderabad and M/s Bharat Petroleum Chemicals Ltd., Mumbai.
Microbial Desulphurisation of Fossil Fuels and Biogas
NEERI, Nagpur, has developed a chemo biochemical process for desulphurisation of gaseous stream containing hydrogen sulphide and successfully demonstrated at pilot scale with a capacity of 100 Nm3 / hr at Vam Organic Chemicals Ltd., Gajraula to assess the techno economic feasibility of the developed process for large scale application. The process has also been demonstrated at Mathura Refinery.
Biosensor for Detection of Pesticide Residues
Visva Bharti University, Shantiniketan has developed a biosensor for detection and estimation of organophosphates such as Metacid 50 and carbamate residues in the environment. The sensor is designed and constructed on the ability of these two pesticides to inhibit the activity of acetylcholinesterase (AchE), an essential enzyme responsible for normal neural transmission. The biosensor is simple, portable and capable of providing rapid data in the field for measurement of trace concentration of these pesticide residues. The biosensor is like a pH paper which changes colour according to the level of contamination. Greater intensity of the yellow colour denotes lower level of contamination while lesser and lesser intensity means higher level of contamination
Detection of Pathogens in Drinking Water
NEERI, Nagpur has developed a user friendly colour based detection system for E.coli (upto 500 cells) in drinking water. Efforts are being made to increase the sensitivity of this test by reducing pathogen load and extending the test to Salmonella and Vibrio.
Biosurfactants from Wastes
NEERI, Nagpur has isolated two biosurfactant-producing microorganisms from oil-contaminated soils and standardized the technology for cost-effective production of biosurfactants from low cost substrates such as distillery and whey waste without any additional source of carbon. It is an ecofriendly substitute for synthetic surfactants.
Bioscrubber’ for Removal of Odours from Industrial Emissions
NEERI, Nagpur has isolated & characterised microbial cultures capable of degrading different odorants in industrial emissions and used for biotransformation of odorants into secondary products or to carbon dioxide and water. A pilot plant is being set up at M/s Jubilant Organosys Ltd. (JOL), Bhartiagram.
