Bioremediation and Sustainable Technologies for Cleaner Environment

Use of pesticide is increasing day by day and the positive aspect renders enhanced crop/food productivity and drastic reduction of vector-borne diseases. However, its unregulated and indiscriminate applications have raised serious concerns in environmental pollution and health effects. Bioremediation methods use naturally occurring microorganisms to detoxify these pollutants and make soil fertile in the process. Bacterial degradation is one of the most environmentally sound, cost effective and quick process for the pesticide contaminated environment. This study includes the usage and the effects of pesticides, bacterial degradation, genetically modified bacteria, enzymatic immobilization approach and few limitations of biodegradation.

Hybrid technologies like nanobioremediation are significant in transforming and detoxifying pollutants which harm the ecosystem. In situ or ex situ it has the potential for large scale clean- up activities with reduced cost and minimal harmful byproducts. Here five nanoscale metallic biosynthesized particles formed the topic of study. Zn, Ag, Au, Fe and Cu particles can be biosynthesized using plant extracts, bacteria, fungi and algae. The potential of these metallic nanoparticles to degrade and remedy various contaminants in the environment has been researched widely. A combination of biosynthesis and remediation lead to sustainable development and ultimately a sustained environment.

India produces around 3000 million tonnes of organic wastes annually. The disposal of ever increasing amount of organic wastes is becoming a serious problem in India. The hygienic disposal of organic wastes by composting is an environmentally sound and economically viable technology resulting in the production of organic fertilizer which is a basic and valuable input in organic farming. The waste collected from the market was grouped into vegetable waste, tapioca waste and sugarcane bagasse. The waste was subjected to initial decomposition under shadow. After that it was allowed for stabilization (24 h) in mud pots before inoculation with Eisenia foetida. Physico chemical analysis was performed on the 51st day. It is found that tapioca generates a rich vermicompost with an acidic pH, low electrical conductivity, high TKN%, phosphorus and potassium. This is followed by sugarcane bagasse with neutral pH, low electrical conductivity, high TKN % and low total organic carbon. Vegetable waste has high phosphorous and potassium and low total organic carbon.

The dairy industry involves processing of raw milk into products like consumer milk, butter, cheese etc. The quantity of water required in a milk processing plant depends upon the size of the plant, generally expressed in terms of the maximum weight of milk handled in a single day, and the processes involved. The daily volume of water required may vary widely, depending mainly on the availability of water and the control of all water using operation in the amount of water needed for the operations which involves continuous flow, for rinsing and washing and is not necessarily proportional to the amount of product processed. Most of the waste water discharged into water bodies, disturbs the ecological balance and deteriorates the water quality. The casein precipitation from waste decomposes further into highly odorous black sludge. Effluent from milk processing unit contains soluble organics, suspended solids, trace organics which releases gases, causes bad taste and odour, impart colour and turbidity, and promote eutrophication. Bioremediation is a ecosafe approach for treating the dairy effluent without disturbing the environment. This review deals about characteristic of dairy effluent and Microorganisms used in the bioremediation of the dairy industry wastes.

In the past few years, there has been a tremendous increase in food waste generation due to rapid urbanization and industrialization. These food wastages have put an emphasis to employ novel techniques for management of waste generated so that waste generation could be reduced to a minimum or these wastes could be converted into some valuable products. Food waste consists of high levels of sodium and moisture and is usually mixed with other types of waste during its collection. Amount of waste generated is largely determined by two factors—population in a given area and its consumption patterns. In order to cope with this huge waste production, advanced and effective waste management systems are to be adopted that can overcome the gap between production and management of waste disposal. Therefore, in this view much technological advancement has occurred in the recent past which has proved to be useful for combating this problem. In this review, a brief introduction to bioremediation for various food industry waste management and advantages and limitation of bioremediation has been discussed.

Soil animals are useful indicators of soil contamination, both before and after the bioremediation. Many toxicity and bioavailability assessment methods utilizing soil animals have been developed for hazard and risk-assessment procedures. Not only the survival of the animals, but also more sensitive parameters like growth, reproduction and community structure have often been taken into account in the assessment. Microorganisms are degrading the contaminants in bioremediation processes, soil animals can also have an important but usually an indirect role in these processes. Soil animals, especially the large ones, can also actively take part in the ecological recovery processes through their own activity. The potential risk of transfer of contaminants accumulated in soil animals to the above-ground food webs should be borne in mind. Earthworms are one of the most important soil animal’s which plays a role in bioremediation of soil for cleaner environment due to their biological, chemical and physical actions. Earthworms can be directly employed within bioremediation strategies to promote biodegradation of organic contaminants. Earthworms have been shown to aerate and bioturbate soils and improve their nutritional status and fertility, which are variables known to limit bioremediation. Earthworms have also been shown to retard the binding of organic contaminants in soils, release previously soil-bound contaminants for subsequent degradation, and promote and disperse organic contaminant degrading microorganisms. This review discusses the earthworm actions upon the soil environment and how they might influence the fate and behaviour of soil associated organic contaminants, subsequently improving bioremediation potential.

Earthworms play an important role in the monitoring of environmental pollution. Hence when exposed to pollution (or) stress condition, physical and deleterious changes are reported to be set in the metabolism of the exposed organism. Karthika et al. (2014) reported that earthworms degrade the paper cup wastes by separating the plastic lining material coated inside the paper cup during the process of vermicomposting. During the degradation process, the organisms take in the plastic resulting in toxicity of the organism (Karthika et al. 2014). Hence attempt was carried out to observe the physiological and morphological modification in the earth worm during the degradation of paper cup wastes. Fortunately there were some abnormal changes noted in the morphology and physiology of earthworm during the initial, middle and final stages of vermicomposting process In the present study, the morphological changes (length, weight) and physiological changes including the antioxidative enzymes (CAT, SOD, GST, GPX), DNA damage and tissue damage occurred during the degradation were investigated in earthworms. However, the overall antioxidant activity was normal during the 1st week of process, later there was increase in its activity during the 12th week and at the 19th week of the process, a drastic reduction in the antioxidant enzyme was noted. However the enzyme activities were observed to be normal in the control. Meanwhile the DNA damage to the earthworm was observed by comet assay where the high level of DNA damage was noted in test animal compared to control. Also the histological examination of the earthworm shows the changes in the external barrier of the tissues of the test animal when compared to the control. The results demonstrate that the earthworm employed for the degradation of paper cup waste undergoes oxidative stress, DNA damage and also tissue damage. However the earthworms have the capable of regaining its metabolic activity when inoculated into the new substrate.

The study has been attempted as a combined process to treat groundwater contamination with nitrate through lab scale bioreactor using dissimilatory denitrifying bacterium Bacillus weihenstephanensis (DS45) and chemical treatments by alum and lime. Nitrate removal was attained up to 80.04% at 156 h by bioreactor process. The residual nitrate, nitrite, ammonium and bacterial growth were effectively removed by addition of lime at 150 mg/L as active coagulants. The treated sample was applied to various disinfectants such as boiling, membrane filtration, UV radiation and chlorination in order to remove bacterial biomass. The bacterial cells of 17 × 10⁴ CFU/ml was completely removed by various disinfectant methods.

An easy, green and economically viable approach for synthesis of copper oxide nanoparticles (CuO NP’s) has been used. CuO NP’s were synthesized using neem extract as reducing agent and were characterized by UV-visible spectroscopy, Transmission electron microscopy (TEM) with SAED pattern, and Fourier transform infrared spectroscopy (FTIR). Its effect in catalytic degradation of Reactive red 120 dyes was determined in presence and absence of NaBH₄ using sunlight as main source. The result showed excellent catalytic activity of nanoparticles in the presence of NaBH_4.

The sorption of Ni (II) metal using Indian gooseberry (Phyllanthus acidus) seeds was studied. The main objective behind carrying out this study was to test the metal removal efficiency of gooseberry seeds for a heavy metal such as Ni(II). The main parameters (kinetic data) included in this study were effect of pH, of contact time, initial metal concentration and dosage concentration studies. The optimum equilibrium found was at 90 min. The equilibrium data was well agreed with Langmuir, Freundlich and Harkins–Jura isotherm models. The adsorption system was found to follow the pseudo-second kinetics. The presence of functional groups and its corresponding effect on Ni (II) metal was observed using FTIR spectroscopy. SEM analysis was carried out to compare the intraparticle pore size of the sorbent material before and after adsorption. The study indicated that gooseberry seed powder activated using sulphuric acid (H₂SO₄) proved to be a promising biosorbent for the removal of Ni(II).

Bioremediation using a variety of microbes for the xenobiotics degradation seems a green solution to the problem of environmental pollution. Different bacteria have the potentials to degrade complex organic compounds into simpler fragments and sometimes achieve complete mineralization. The present study, deliberate the synthesis of silver nanoparticles (AgNPs) using different bacillus species like B. megaterium (SIV01), B. subtilis (SIV02), B. megaterium (MNS1), B. subtilis (001), B. licheniformis (P-2) and their ability to decolorize the dye Congo red. The synthesized AgNPs were characterized using UV visible spectrophotometer, FTIR and SEM. The UV Vis Spectrum results showed that the Bacillus megaterium (SIV01) to be the most potential organism for the synthesis of AgNPs among the different strains used which is confirmed by high absorbance value at 450 nm. The adsorption and decolourization capacity was found to be high for all the strains which was exihibited by high Langmuir and Freundlich isotherm constants. The synthesized silver nanoparticles showed significant antibacterial activity against E. coli. Interestingly, the synthesized silver nanoparticles showed antibacterial activity against its own source microorganisms, this peculiar behaviour exhibited by the bacillus silver nanoparticles, is yet to be explored.

The major environmental pollution encountered by the textile effluent is the presence of color, dissolved solids and refractory materials such as detergents, organic pollutants, heavy metal ions which might arise from dyes. Discharge of the textile effluent to the nearby water body alters the physical, chemical and biological nature of the water bodies, seep into the aquifer, decreases the oxygen level in water leading to death of the aquatic biota and biomagnification. The present study was developed to comprehend the pollution caused by the local textile mill to the environment and their remediation. The physicochemical analyses of discharged effluent, adjacent soil and the cultivated crop near the discharge point at Tirupur, Tamil Nadu, India were analyzed and found to be altered. The organic matter and total available nitrogen content in the soil was found to be reduced, the high concentration of heavy metal in the seeds of Pennisetum typhoides characterized with SEM–EDX indicates soil lost its fertility. The 16S rRNA sequence of the predominant bacterial isolates exhibiting maximum resistant level towards heavy metal was deposited in NCBI Genebank and designated as Bacillus cereus, Pseudomonas putida. Further, the efficacy of the immobilized strains with Luffa aegyptiaca to accumulate/uptake heavy metals (Cr and Zn) under optimized conditions and their subsequent toxicity assessment in response to waste water irrigation were analyzed.

Cow dung, an excreta of bovine animal is a cheap and easily available bioresource on earth. Many traditional uses of cow dung such as burning as fuel, mosquito repellent and as cleansing agent are already known in India. Cow dung harbours a diverse group of microorganisms that may be beneficial to humans due to their ability to produce a range of metabolites. Nowadays, there is an increasing research interest in developing the applications of cow dung microorganisms for biofuel production and management of environmental pollutants. Use and misuse of pharmaceuticals, pesticides and petrochemicals by man is causing havoc with nature, as they persist as such or as their toxic metabolites. These pollutants bioaccumulate in environment, and they ultimately reach man through various means. They are hazardous because of potential toxicity, mutagenicity, carcinogenicity and genotoxicity. Bioremediation methods use naturally occurring microorganisms to detoxify man-made pollutants so that they change pollutants to innocuous products that make soil fertile in the process. This review discusses about using cow dung as bioremediation for pharmaceuticals, pesticides and petrochemicals for cleaner environment.

India has a large network of textile industries of varying capacity and textile effluent is one of the main contributors of water pollution and it adversely affects fauna and flora. Phytoremediation technology can be effective approach for remediating contaminated sites of such textile dyeing effluents. The objective of this research is to study the efficiency of aquatic macrophytes plant contributed for remediation of textile waste water. In this study, lab scale wetland was constructed and tested with Alternanthera sessilis, sand and gravel as filter. Results indicated that, textile effluent degradation and significant reductions in TS (78%), TDS (83%), TSS (38%), COD (65%), BOD₅ (66%), chloride (44%), hardness (76%) and TDS (59%) were observed by the combined use of plants within 24 hrs. The removal efficiency of unplanted were TS (50%), TDS (50%), TSS (29%), COD (27%), Hardness (57%), Chloride (26%), BOD₅ (27%) respectively. When compared the removal efficiency of planted with unplanted, planted shows a maximum removal the results showed that the removal efficiencies of the organics TDS, COD and BOD₅ were improved significantly with the extension of HRT. This objective of study and efficiency of plants and proposed mechanism of aquatic macrophytes plant contributed for remediation of textile waste water.

Bioconversion offers a cheap and safe method of not only disposing the agricultural residues, but also it has the potential to convert lignocellulosic wastes into usable forms such as reducing sugars that could be used for ethanol production. In this present study, a formulated bio-control agent Trichoderma viride collected from the farmers of Wayanad, Kerala, India and an indigenous Trichoderma spp isolated from the paddy fields of Thiruporur area, Tamil nadu, India were used to evaluate the efficiency of cellulolytic property for the conversion of cellulosic wastes such as vegetable waste and sugarcane bagasse to simple sugars. Further the same was used as substrate for the synthesis of bio-ethanol by Saccharomyces cerevisiae. Cellulase production ability of both fungi using substrates carboxy methyl cellulose, vegetable waste and bagasse were estimated and the amount of cellulase produced by Trichoderma viride was 396.6, 361.6 and 466.6 U/ml and the amount of cellulase produced by Trichoderma spp KT was estimated as 198.3, 233.3 and 245 U/ml from the corresponding substrates. Among the all substrate used, sugarcane bagasse had served as a good substrate when compared to others. Bioconversion of the same saccarified broth was used for bio-ethanol production. The production rate estimated in carboxy methyl cellulose, vegetable waste and sugarcane bagasse was 70 and 100% respectively by Trichoderma viride where as it was 54.6, 66.3 and 83.3% in the fermented broths of Trichoderma spp KT. In conclusion, the cellulosic waste can be very well used as a resource for bio-ethanol production. The synergistic interactions of Trichoderma viride and Saccharomyces cerevisiae can play a significant role in bioconversion of waste into a renewable energy.

Dwindling of petroleum-based fuels together with their frightening environmental effects has enforced the emergence of lignocellulose-based biorefineries. Being most abundant and bio-renewable, lignocellulosic biomass holds enormous potential for production of biofuels, bio-based chemicals and materials for a sustainable energy future. Utilization of lignocellulosic materials in a biorefinery requires a well-designed pre-treatment technology with reasonable processing cost for deconstruction of the lignocellulose complex. Current technologies rely on chemical, physico-chemical and biochemical conversion routes for effective hydrolysis of lignocellulosic materials. Identification of novel enzymes and microbes to counteract the pre-treatment-induced inhibitory products is a prime area of research as chemical detoxification method carries financial constrains. Valorization of biomass is greatly influenced by generation of co-products in biorefining processes and their selective recovery, which may considerably reduce the cost involved in biofuel production. The lab-to-industry transition of a bioprocess technology necessitates a sound techno-economical evaluation for optimum product yield to hit the market place.

To reduce the production cost of polyhydroxyalkanoates (PHAs), the feasibility of using a lignocellulosic substrate—paddy straw as carbon source was examined. The design of an optimum and cheap medium for high level production of PHAs by Ralstonia eutropha was attempted by using response surface methodology. Based on the Plackett Burman design, K₂HPO₄ and MgSO₄ were selected as the most critical mineral salts. Subsequently the optimum combination of the selected factors and the major carbon source, hydrolysed paddy straw were investigated by the Box–Behnken design.

Potential of producing liquid transportation biofuels is demanding because of depleting fossil fuels. The aim of this study is to produce bioethanol from Parthenium hysterophorus by statistical modeling and optimization. Response surface methodology based Box–Behnken design was employed to optimize the pre-treatment of P. hysterophorus using tartaric acid. Pre-treatment of plant tissue was confirmed through Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and visualization in photographic image. Then, cellulases enzyme was used for hydrolysis of cellulose in cellulignin (cellulose and lignin) and then detoxified with lime. Finally, co-fermentation of Kluyveromyces marxianus with Saccharomyces cerevisiae, Fusarium oxysporum, Zymomonas mobilis and Klebsiella oxytoca was performed for bioethanol production. Ethanol concentrations of 1.248, 1.195, 1.879 and 1.616% (v/v) were obtained for mixed culture of K. marxianus with Z. mobilis, K. oxytoca, F. oxysporum and S. cerevisiae respectively after 72 h of fermentation. Hence, it is inferred that, the mixed culture of K. marxianus and F. oxysporum was found to be the best combination for ethanol production from P. hysterophorus.

In the present study, the fermentative hydrogen-producing bacterial strain KTSMBNL 11 was isolated from municipal sewage sludge and identified as Klebsiella pneumoniae based on 16S rDNA gene sequence analysis. Batch experimental studies were performed to determine the effects of initial pH, temperature and substrate concentration on hydrogen production. At pH 6.0 and 36 °C, the maximum hydrogen production rate of 525 ml/l/h was obtained with 30 g/l of glucose, and the highest yield of 2.57 mol/mol G was achieved with an initial glucose concentration of 5 g/l. During anaerobic fermentation, the main soluble metabolites obtained were 2, 3-butanediol and ethanol. Under these optimal conditions, Klebsiella pneumoniae has a higher hydrogen yield compared with other pure bacterial cultures reported in the literature. Thus, Klebsiella pneumoniae is a promising option as an effective hydrogen-producer.

With the passage of time, and with the rise in demands of population Industrialization and new technologies has also augmented. But this rise is now affecting the various ecosystems and thus contaminating the environment. Accumulation of heavy metals has now become a serious concern. Nature has provided us enormous ways for the depletion of these heavy metals viz: leaching, plant uptake, erosion and deflation. But as contaminants are now reached beyond the limit of nature and thus requires alternative ways with lesser or no side effects. The best way out to treat these contaminants is bioremediation. Bioremediation is a process that utilizes plants and microbes for the transformation of heavy metals. There are many microbes that have developed specialized mechanism for heavy metals. Some microbes are found to develop a mechanism through which they are able to sequester and immobilize metals, while some are found to enhance the solubility of metals, some of them oxidizes or reduces them to non toxic or comparatively lesser toxic forms. Now the genetic engineering is also used so that the traits of one organism can be transfer to other and thus one microbe can simultaneously detoxify more than one contaminant. In this chapter, efforts have been made to simplify the causes, effects, possible treatment, mechanism and the future aspect of bioremediation.

Five different samples (3 effluent samples and 2 soil samples) were collected from CETP in SIPCOT, Perundurai, Erode District, Tamil Nadu and were serially diluted and cultured. 8 different fungal colonies were isolated. Of these fungal isolates, 4 colonies were selected for their ability to decolorize Reactive Red 120, Reactive Black 5 and Direct Red 81 which are synthetic dyes. These selected isolates were identified as Pleurotus ostreatus, Aspergillus niger, Penicillium simplicissimum and Penicillium chrysosporium. Among the selected isolates, Pleurotus ostreatus revealed the maximum percentage of the reactive dye removal of about 76, 64 and 62% for Reactive Red 120, Reactive Black 5 and Direct Red 8 respectively. Further, Four different fungal consortium (FC) were developed, of which FC1 consisting of Pleurotus ostreatus, Aspergillus niger, Penicillium simplicissimum, Penicillium chrysosporium exhibited the highest dye removal percentage of 78% for Reactive Black 5.

Biosurfactants, the surface-active compounds produced by microorganisms, have bright prospects in the bioremediation of oil spills. They can also serve as substitutes to synthetic surfactants in food and cosmetic industries. In this study, bacterial strains from soil samples exposed to petroleum hydrocarbons were screened using drop collapse, oil displacement and hemolytic activity tests. Six isolates showed encouraging results in these tests. Based on further assessment of emulsification activity and surface tension reduction, three of the isolates AS03, AS09 and AS01 were judged to be good biosurfactant producers. 16S rRNA gene sequencing confirmed the identity of the best isolate AS03, to be Bacillus licheniformis. Optimization of biosurfactant production and crude oil emulsification by this isolate was attempted using response surface methodology. The optimum levels of three significant variables viz., glucose, yeast extract and toluene were ascertained to be 10.5 g/L, 10 g/L and 5% (v/v), respectively, which resulted in 54.79% emulsification activity (E_24%). The biosurfactant was characterized to be of lipopeptide nature based on the FTIR spectrum. These bacterial strains and the produced biosurfactant hold potential for oil spill clean-up and related environmental applications.

The present study was aimed to isolate and characterize a novel thermo tolerant melanoidin degrading bacteria from its natural environment. A total number of 35 bacterial strains were isolated among them 2 strains labelled A and H exhibited a maximum of 10% ethanol tolerance and were able to grow at 60 °C. In which, a novel strain A exhibited maximum decolourization 72%, BOD, COD and was able to grow at higher temperature in comparison with other strains. Further, to confirm the identity, it was subjected to morphological, biochemical and molecular characterization. Based on the analysis the identity of the strain A was confirmed as Bacillus tequilensis. The production of MnP and laccase enzymes was observed and decolourization efficiency was analysed through FTIR, the results revealed that most of the predominant compounds present in the control sample were degraded. The reported novel thermo tolerant bacterium Bacillus tequilensis was able to decolorize the melanoidin pigment of distillery effluent more efficiently even at higher temperature than the bacterium reported earlier.

Industrial effluents are one of the major sources of heavy metal contaminations and cause significant environmental problems to the aquatic life. Some heavy metals are easy soluble and unable to separate easily using conventional chemical methods. Hence biological methods like biosorption/bioaccumulation were carried out for the removal of heavy metals from the environment. The objective of the present study is to optimize algal growth in various growth media. Additionally the ability of three species of blue green algae, Chlorella sp. and Neochloris sp. and an unidentified isolate to adsorb chromium was tested. The presence of chromium in the samples was analyzed using AAS, SEM-EDX and FT-IR. The results showed that highest algal growth rate was observed in BG11 medium with solution B. The unidentified cyanobacterial isolate exhibited higher chromium removal capacity (75.63%) followed by Chlorella sp. (44.37%) and Neochloris sp. (72.5%).