Ecological and Biochemical Studies On Cyanobacteria of Cochin Estuary and Their Application as Source of Antioxidants

The main objectives of the present investigation were to evaluate the qualitative and quantitative distribution of natural cyanobacterial population and their ecobiological properties along the Cochin estuary and their application in aquaculture systems as a nutritional supplement due to their nutrient-rich biochemical composition and antioxidant potential. This thesis presents a detailed account of the distribution of cyanobacteria in Cochin estuary, an assessment of physico-chemical parameters and the nutrients of the study site, an evaluation of the effect of physico-chemical parameters on cyanobacterial distribution and abundance, isolation, identification and culturing of cyanobacteria, the biochemical composition an productivity of cyanobacteria, and an evaluation of the potential of the selected cyanobacteria as antioxidants against ethanol induced lipid peroxidation. The pH, salinity and nutritional requirements were optimized for low-cost production of the selected cyanobacterial strains. The present study provides an insight into the distribution, abundance, diversity and ecology of cyanobacteria of Cochin estuary. From the results, it is evident that the ecological conditions of Cochin estuary support a rich cyanobacterial growth.

Novel Approaches to Biodegradable Polymers: Synthesis and Biodegradation Studies

Biodegradable polymers have opened an emerging area of great interest because they are the ultimate solution for the disposal problems of synthetic polymers used for short time applications in the environmental and biomedical field. The biodegradable polymers available until recently have a number of limitations in terms of strength and dimensional stability. Most of them have processing problems and are also very expensive. Recent developments in biodegradable polymers show that monomers and polymers obtained from renewable resources are important owing to their inherent biodegradability, biocompatibility and easy availability. The present study is, therefore, mostly concemed with the utilization of renewable resources by effecting chemical modification/copolymerization on existing synthetic polymers/natural polymers for introducing better biodegradability and material properties.The thesis describes multiple approaches in the design of new biodegradable polymers: (1) Chemical modification of an existing nonbiodegradable polymer, polyethylene, by anchoring monosaccharides after functionalization to introduce biodegradability. (2) Copolymerization of an existing biodegradable polymer, polylactide, with suitable monomers and/or polymers to tailor their properties to suit the emerging requirements such as (2a) graft copolymerization of lactide onto chitosan to get controlled solvation and biodegradability and (2b) copolymerization of polylactide with cycloaliphatic amide segments to improve upon the thermal properties and processability.

Paddy Field Cyanobacteria : Diversity and Pesticide Tolerance

School of Environmental Studies, Cochin University of Science and Technology

Modification of Linear Low Density Polyethylene for Improved Photo and Biodegradation

LLDPE was blended with poly (vinyl alcohol) and mechanical, thermal, spectroscopic properties and biodegradability were investigated. The biodegradability of LLDPE/PVA blends has been studied in two environments, viz. (1) a culture medium containing Vibrio sp. and (2) a soil environment over a period of 15 weeks. Nanoanatase having photo catalytic activity was synthesized by hydrothermal method using titanium-iso-propoxide. The synthesized TiO2 was characterized by X-Ray diffraction (XRD), BET studies, FTIR studies and scanning electron microscopy (SEM). The crystallite size of titania was calculated to be ≈ 6nm from the XRD results and the surface area was found to be about 310m2/g by BET method. SEM shows that nanoanatase particles prepared by this method are spherical in shape. Linear low density polyethylene films containing polyvinyl alcohol and a pro-oxidant (TiO2 or cobalt stearate with or without vegetable oil) were prepared. The films were then subjected to natural weathering and UV exposure followed by biodegradation in culture medium as well as in soil environment. The degradation was monitored by mechanical property measurements, thermal studies, rate of weight loss, FTIR and SEM studies. Higher weight loss, texture change and greater increments in carbonyl index values were observed in samples containing cobalt stearate and vegetable oil. The present study demonstrates that the combination of LLDPE/PVA blends with (I) nanoanatase/vegetable oil and (ii) cobalt stearate/vegetable oil leads to extensive photodegradation. These samples show substantial degradation when subsequent exposure to Vibrio sp. is made. Thus a combined photodegradation and biodegradation process is a promising step towards obtaining a biodegradable grade of LLDPE.

Biodegradation of phenolic compounds in different ecosystems in Cochin

The purpose of this study is to determine the ability of specifically adapted bacteria to degrade phenol and to quantify the rate of biodegradation at. Different concentrations by mixed as well as individual isolates. Regular quantitative analysis of phenolics and aerobic phenololytic heterotrophs from five different ecosystems were done during 1990-1991, and the ability of microorganisms isolated from those areas, to utilize phenol, o-cresol and orcinol was also studied. In addition, data on environmental parameters like temperature, dissolved oxygen, salinity, pH, organic carbon and nutrients were also collected during the period of study The present study is one of its first kind in natural aquatic environment and has aimed to bring out some idea about the potential phenol biodegrades in such environments where the phenol concentration is beyond permitted level.

Evaluation of cyanobacteria for biomass production and effluent treatment

The microalgae gained importance as food and feed as well as source of fine chemicals since the l960’s. Spirulina became the trend setter due to its easily culturable properties as well as nutritional composition. A rapid expansion of microalgal industry occurred in the Asia-Pacific region as microalgae came to stay as a health food supplement. Microalgae have been an integral component of oxidation ponds usually incorporated with wastewater treatment. Over the last few decades, efforts have been made to apply intensive microalgal cultures to perform biological tertiary treatment of secondary effluents. Given the limited number of species still available for commercial exploitation, it is imperative to isolate and cultivate those photosynthetic organisms with high growth rate and biomass accumulation, which could play the dual role of cleaning the wastewater and also providing useful biomass. This has been the objective of this study ie. 0 To develop pure cultures of local isolates of Cyanobacteria for extraction of biochemicals of commercial value 0 To couple biomass production with effluent treatment

Aquatic Cyanobacteria Isolated from Cochin: Growth characteristics and bioactive impact on selected microflora

Aquatic ecosystem in the south west coast of India is noted for its diversity of habitats. Very often these environments turn bluegreen when the bloom of bluegreen algae (cyanobacteria) appear consequent to eutrophication. This phenomenon occursin these habitats one after the other or simultaneously. This conspicuousness make one curious enough to know more about these nature’s gift bestowed upon mankind. While persuing the literature on the magnificent flora) it is understood that it may provide food fertilizer, chemicals and bioactive substances. These bioactive substances are likely to be involved in regulating natural populations and are potentially useful as biochemical tools and as herbicidal or biocontrol agents. The role of cyanobacteria in the aquatic food chain and contribution in abatement of heavy metals from the natural environment are well documented. Considering the manifold utilization of the flora and their significance in the food chain, the present investigation has been undertaken

Occurrence and Distribution of a Diatom-Diazotrophic Cyanobacteria Association during a Trichodesmium Bloom in the Southeastern Arabian Sea

Symbiotic diatom-diazotrophic cyanobacteria association (DDA) of Rhizosolenia hebetata and Rhizosolenia formosa with endosymbiotic cyanobacteria Richelia intracellularis was noticed and documented for the first time during a bloom of the cyanobacterium Trichodesmium erythraeum in the oligotrophic shelf waters along Kochi and Mangalore transects, southeastern Arabian Sea (SEAS), during spring intermonsoon (April 2012). Although the host is frequently seen, the symbiont is rarely reported in the Indian EEZ. The presence of nitrogen-fixing symbiotic association of Rhizosolenia-Richelia along with Trichodesmium erythraeum highlights the significance of DDAs on the nutrient and energy budgets of phytoplankton in the oligotrophic environments of the Arabian Sea during spring intermonsoon

Effect of Amylase Producing Vibrios From the Benthic Environment on the Biodegradation of Low Density Polyethylene-Dextrin Blends

Low-density polyethylene was mixed with dextrin having different particle sizes (100, 200 and 300 mesh). Various compositions were prepared and their mechanical properties were evaluated and thermal studies have been carried out. Biodegradability of these samples has been checked using liquid culture medium containing Vibrios (an amylase producing bacteria), which were isolated from marine benthic environment. Soil burial test was done and reprocessability of these samples was evaluated. The results indicate that the newly prepared blends are reprocessable without sacrificing much of their mechanical properties. The biodegradability tests on these blends indicate that these are partially biodegradable

Biodegradation Of Phenol Using Spent Substrate Of Pleurotus Sp.

Phenol is an aromatic hydrocarbon which exists as a colorless or white solid in its pure state. Over the past several decades, there is growing concern about wide spread contamination of surface and ground water by phenol, due to rapid development of chemical and petrochemical industries. Phenol affects aquatic life even at relatively low concentration (5-25mg/L). Treatment for removal of phenol includes chemical as well as biological processes. Studies show that ligninases such as Lignin Peroxidase and Laccase, produced by Pleurotus sp., can degrade phenol. Spent substrate of Pleurotus mushrooms consists of ligninases. Present work was to investigate the potential of spent substrate of edible mushroom P. ostreatus for biodegradation of phenol. P. ostreatus was cultivated on paddy straw. After harvest, spent substrate was utilized for phenol degradation. According to the enzyme profile of two ligninases present in the spent substrate of P. ostreatus, maximum specific activity for Laccase was observed in 35 day old spent substrate and LiP activity was maximum in 56 day old spent substrate, which together contributed significantly for removal of phenol. Spent substrate of 35th and 56th day were each incubated with phenol sample (1:1w/v) for one day, which resulted in degradation of phenol by 48% and 45% respectively. From these results it appears that, spent substrate of P. ostreatus can be used effectively to remove phenol from industrial effluents

Ionomer Compatibilized Low Density Polyethylene - Tapioca Starch Blends Biodegradability and Photodegradability

Biodegradation is the chemical degradation of materials brought about by the action of naturally occurring microorganisms. Biodegradation is a relatively rapid process under suitable conditions of moisture, temperature and oxygen availability. The logic behind blending biopolymers such as starch with inert polymers like polyethylene is that if the biopolymer component is present in sufficient amount, and if it is removed by microorganisms in the waste disposal environment, then the base inert plastic should slowly degrade and disappear. The present work focuses on the preparation of biodegradable and photodegradable blends based on low density polyethylene incorporating small quantities of ionomers as compatibilizers. The thesis consists of eight chapters. The first chapter presents an introduction to the present research work and literature survey. The details of the materials used and the experimental procedures undertaken for the study are described in the second chapter. Preparation and characterization of low density polyethylene (LDPE)-biopolymer (starch/dextrin) blends are described in the third chapter. The result of investigations on the effect of polyethylene-co-methacrylic acid ionomers on the compatibility of LDPE and starch are reported in chapter 4. Chapter 5 has been divided into two parts. The first part deals with the effect of metal oxides on the photodegradation of LDPE. The second part describes the function of metal stearates on the photodegradation of LDPE. The results of the investigations on the role of various metal oxides as pro-oxidants on the degradation of ionomer compatibilized LDPE-starch blends are reported in chapter 6. Chapter 7 deals with the results of investigations on the role of various metal stearates as pro-oxidants on the degradation of ionomer compatibilized LDPE-starch blends. The conclusion of the investigations is presented in the last chapter of the thesis.

Biochemical and Biotechnological Studies on the Cyanobacterium Synechocystis salina Wislouch

The group cyanobacteria includes a large number of organisms characterised by a low state of cellular organization. Their cells lack a well defined nucleus. Cell division is by division of the protoplast by an ingrowth of the septum. These organisms are characterised generally by a blue green colouration of the cell, the chief pigments being chlorophyll-a, carotenes, xanthophylls, C phycocyanin and C phycoerythrin. The product of photosynthesis is glycogen. These organisms lack flagellate reproductive bodies and there is a total lack of sexual reproduction. They are also unique because of the presence of murein in the place of cellulose (cell wall) and the absence of chloroplast, mitochondria and endoplasmic reticulum. Just like bacteria some of them possess Plasmids and can fix atmospheric nitrogen. In the present study growth kinetics, heavy metal tolerance, tolerance mechanisms, heavy metal intake, and antibacterial activity of §ynechocystics salina Wislouch - a nanoplanktonic, euryhaline, Cyanobacterium present in Cochin back waters has been carried out for the potential biotechnological application of this organism. _§; salina occur as small spherical cells of 3n diameter (sometimes in pairs) with bluish green colour. The species is characterised by jerky movement of the cells and is structrually similar to other cyanobacteria

Bioremediation of Hydrocarbons by Lysinibacillus fusiformis BTTS10

There exists a need for potential microorganism that could facilitate effective bioremediation of crude oil pollutants in the environment. Hence it was desired to isolate a potential bacterium from marine sediment, which often experiences oil pollution and develop a bioprocess for crude oil biodegradation. In the present study the sediment deposits in the beach of Munakkal, Trichur dist, Kerala, collected immediately after the major event Tsunami in 2004 was collected and analyzed by enrichment culture technique towards isolation of potential strains that could degrade crude oil and its fractions. From the results obtained it was found that the sediment deposits harbor several bacteria with potential for degrading hydrocarbons. However, among the strains obtained, isolate no. BTTS 10 showed capabilities for utilizing both alkanes and aromatic hydrocarbons and hence the same was selected for further studies.

“Studies on extracellular enzyme production during growth of Pleurotus sp. on lignocellulosic agriwaste and the utilization of spent mushroom substrate”

Commercially, Pleurotus spp. of mushroom are cultivated in bags. After mushroom cultivation, spent substrate remains as residual material. Proper recycling of spent substrate is beneficial for our economy. Spent substrate can be utilized for various other value added purposes through the proper knowledge of its components. Composition of various components depends on the activity of extracellular enzymes in the spent substrate. The present study was conducted to know the enzyme profile of some major extracellular enzymes - cellulase, hemicellulase (xylanase), pectinase and ligninase (lignin peroxidase and laccase) and to estimate cellulose, hemicellulose, pectin and lignin in the substrate. The use of spent substrate as a source of fibre and ethanol, and in the biodegradation of phenol by Pleurotus spp. was also investigated