Phylogeny in Aid of the Present and Novel Microbial Lineages: Diversity in Bacillus

Bacillus represents microbes of high economic, medical and biodefense importance. Bacillus strain identification based on 16S rRNA sequence analyses is invariably limited to species level. Secondly, certain discrepancies exist in the segregation of Bacillus subtilis strains. In the RDP/NCBI databases, out of a total of 2611 individual 16S rDNA sequences belonging to the 175 different species of the genus Bacillus, only 1586 have been identified up to species level. 16S rRNA sequences of Bacillus anthracis (153 strains), B. cereus (211 strains), B. thuringiensis (108 strains), B. subtilis (271 strains), B. licheniformis (131 strains), B. pumilus (83 strains), B. megaterium (47 strains), B. sphaericus (42 strains), B. clausii (39 strains) and B. halodurans (36 strains) were considered for generating species-specific framework and probes as tools for their rapid identification. Phylogenetic segregation of 1121, 16S rDNA sequences of 10 different Bacillus species in to 89 clusters enabled us to develop a phylogenetic frame work of 34 representative sequences. Using this phylogenetic framework, 305 out of 1025, 16S rDNA sequences presently classified as Bacillus sp. could be identified up to species level. This identification was supported by 20 to 30 nucleotides long signature sequences and in silico restriction enzyme analysis specific to the 10 Bacillus species. This integrated approach resulted in identifying around 30% of Bacillus sp. up to species level and revealed that B. subtilis strains can be segregated into two phylogenetically distinct groups, such that one of them may be renamed

Bioplastics

433-445Plastics and polymers have become a part of our life today. The annual consumption of plastics in India is 2 kg/person/y. In the other developed countries the per capita consumption of plastics is of the order of 60 kg/y. Some naturally occurring plastic materials have been made use of by man from the earliest times, e.g., Lac and Amber. Today, almost all the plastics are manufactured synthetically and they have much better properties than naturally occurring plastics. The basic raw material for all the modern plastics is crude oil and natural gas. Due to their non-biodegradable nature, environmentalists are campaigning against their production and usage. In India, plastic wastes accounts for 1 to 4 per cent by weight of the total of 80,000 metric tonnes of Municipal solid waste generated daily. In USA, of the 4 lakh tonnes of garbage generated everyday, plastic constitute 30 per cent of its volume. Plastics (polymers) can be degraded by three different processes, either independently or in combination : (i) Light or high energy radiation, (ii) Heat, and (iii) Microbes. In response to increasing public concern over environmental hazard caused by plastic, many countries are conducting various solid waste management programmes including plastic waste reduction by development of biodegradable plastic material. There is an intense research for making the biodegradable plastic material. Some biodegradable plastic materials under development are: (i) Poly hydroxy alkanoates (PHAs), (ii) Poly-lactides, (iii) Aliphatic poly-esters, (iv) Polysaccharides, and (v) Co-polymers and/or blends of above. However, it is possible to produce biodegradable plastics from bio-wastes with the help of a syntrophic population of microbes of diverse origins. This will help to reduce waste management problems and improve environment

Waste Management and Production of Future Fuels

184-207The ever-increasing demand for energy, the diminishing energy source and the problem of environmental pollution have raised public awareness to the need for a non-polluting renewable energy source. Biowastes, a potential renewal energy source of different origins arc associated with a negative value due to disposal and pollution cost. Biological wastes of different origins (agricultural, industrial, municipal and domestic) undergo slow and uncontrolled degradation, which leads to environmental pollution and their disposal is a big problem due to high transportation costs and scarcity of dumping sites. Anaerobic degradation of these wastes to useful products like energy rich fuel gases can stabilize them and also serve as renewable energy source. Microbial production of methane from different biological wastes has been studied on a wide range of wastes. Thus. wastes utilization rather than its treatment emphasizes upon shifting the process from reducing the potential for pollution to synthesis of useful products. like gases and chemicals. Biomass amenability to conversion depends largely on the characteristic of the biomass (substrate) and the process requirements for conservation technology under consideration. Among the various by-products, which can be obtained by the fermentation of waste biomass, hydroger, has gained importance. It is regarded as the strongest contender as the clean fuel of the future. Microbial production of hydrogen has been demonstrated but the yields are quite low. large scale and continuous production is still in the incipient stage. In nature, wherever organic material is degraded microbially, under anaerobic condition and in the absence of sulphate and nitrate. methane is produced. When organic matter decompose without oxygen, the anaerobic bacteria produce methane and carbon dioxide. Anaerobic digestion provides appropriate solutions to problem associated with waste disposal and also generates biofuels as by-products

Membrane Separation to Improve Degradation of Road Side Grass by Rumen Enhanced Solid Incubation

Membrane separation proved to be an excellent means to maintain high residence time of microorganisms in an anaerobic hydrolysis reactor, and relatively low concentration of hydrolysis products. The microbial biocommunity typical for the rumen environment could be maintained, and the reactor efficiency of the reactor improved. Less than 4 days were reqired to reach almost complete hydrolysis of the grass fed into the reactor. To avoid blocking of the membrane unit, a backwash system is necessary. The membranes needed to be backwashed every 20 min with 4 bar gas-pressure for 10 s. After this treatment the initial permeability was regained. The plant was operated with a flux of 12 ml h-1cm-2 on average. The transmembrane pressure was in the range of 0.8-0.9 bar. 90% of the dissolved fatty acids permeated through the membrane