| || Effect of Fluctuating temperature Regime on Psychrophilic Anaerobic Digestion of Nightsoil
Author : Ramana, K.V. ;Alam, S.I.;Singh, Lokandra
Source : Defence Science Journal ; Vol:49(2) ; 1999 ; pp 135-140
Subject : 61 Medical Sciences;612 Physiology
Keywords : Hydrogenotrophic methanogens ;Volatile fatty acids;Anaerobic digestion
Abstract : "The effect of temperature fluctuation on anaerobic digestion of nightsoil using 10 °C adapted inoculum was studied. The digester was subjected to repeated temperature cycling of 10 °C and 30 °C. The total biogas, CH/sub 4/ and H/sub 2/S content, volatile fatty acids and microbial counts were compared with control digesters. No significant deleterious effect was noticed during initial temperature shock of one week. However, repeated exposures reduced the counts of hydrogenotrophic methanogens. There was no effect on the content of CH/sub 4/ and H/sub 2/S in the biogas."
| || Psychrotrophic Hydrolytic Bacteria from Antartica and other low Temperature Habitats
Author : Ramana, K.V.;Singh, Lokendra;Saxena, Nalini
Source : Defence Science Journal ; Vol:50(2) ; 2000 ; pp 177-182
Subject : 57.089 Biomedical Sciences
Keywords : Psychrotrophic hydrolytic bacteria;Amylolytic bacteria;Hydrolysed denatured protein substrate;Monomeric synthetic lipid substrates
Abstract : "Samples of water, soil, lake sediments and blue-green algal mats from Antarctica were processed for enumeration, isolation and screening of psychrotrophic hydrolytic bacteria. Amylolytic bacteria were preponderant (75 per cent) in the blue-green algal mat samples. Protease, lipase, amylase and urease producing bacteria were also isolated from the samples. Biochemical characteristics indicated that the isolates mainly comprised Pseudomonas and Bacillus species. Proteases and lipases of antarctic bacteria strains preferably hydrolysed denatured protein substrate and water soluble monomeric synthetic lipid substrates, respectively. "
| || Microbial degradation of Organic Wastes at Low Temperatures
Author : Ramana, K.V.;Singh, Lokendra
Source : Defence Science Journal ; Vol:50(4) ; 2000 ; pp 371-382
Subject : 579 MicroBiology;57.089 Biomedical Sciences
Keywords : Organic wastes;Organic waste disposal method;Aerobic waste treatment method;Artificial heating;Non conventional energy sources;Polymeric materials;Digester insulation;Anaerobic digesters
Abstract : Microbial degradation of organic wastes mainly comprising animal and human wastes, is drastically reduced at extreme low temperatures. For the biodegradation of these wastes, technological inputs are required from disciplines like microbiology, biochemistry, molecular biology, digester modelling and heat transfer at extreme low temperature climates. Various steps in the process of biodegradation have to be studied to formulate an effective organic waste disposal method. Anaerobic digestion of organic wastes is preferred over aerobic waste treatment method, since it yields biogas as a by-product, which in turn can be utilised for heating the digester contents to increase its efficiency. Furthermore, one of the possibilities that can be explored is the utilisation of high rate anaerobic digesters which maintain temperature by means of artificial heating. It is either met by non-conventional energy sources, such as solar and wind energy, or by expending liquid fuels. In addition, insulation of the digester with polymeric materials and immobilisation of slow growing bacterial population may enhance the digester performance to a great extent. In spite of several developments, inoculum adaptation is considered to be one of the essential steps for low temperature anaerobic digestion to obtain methane as a by-product. With advancements in recombinant DNA technology, it may be possible to increase the efficiency of various microbial population that take part in the anaerobic digestion. However, till date, the options available for low temperature biodegradation are digester insulation, inoculum adaptation, and use of high rate/second-generation digesters.