Kalpana Mody

Kappaphycus alvarezii as a source of bioethanol.

The present study describes production of bio-ethanol from fresh red alga, Kappaphycus alvarezii. It was crushed to expel sap--a biofertilizer--while residual biomass was saccharified at 100 °C in 0.9 N H2SO4. The hydrolysate was repeatedly treated with additional granules to achieve desired reducing sugar concentration. The best yields for saccharification, inclusive of sugar loss in residue, were 26.2% and 30.6% (w/w) at laboratory (250 g) and bench (16 kg) scales, respectively. The hydrolysate was neutralized with lime and the filtrate was desalted by electrodialysis. Saccharomyces cerevisiae (NCIM 3523) was used for ethanol production from this non-traditional bio-resource. Fermentation at laboratory and bench scales converted ca. 80% of reducing sugar into ethanol in near quantitative selectivity. A petrol vehicle was successfully run with E10 gasoline made from the seaweed-based ethanol. Co-production of ethanol and bio-fertilizer from this seaweed may emerge as a promising alternative to land-based bio-ethanol.

Sulphated polysaccharides of Codium dwarkense Boergs. from the west coast of India: chemical composition and blood anticoagulant activity.

Bioassay-guided purification of sulphated polysaccharides from a green marine alga, Codium dwarkense, yielded two products, which contained sulphated arabinan and sulphated arabinogalactan. The product containing arabinan sulphate exhibited stronger blood anticoagulant activity than the one containing sulphated arabinogalactan.

A new sulfated polysaccharide with potent blood anti-coagulant activity from the red seaweed Grateloupia indica

Abstract A sulfated galactan has been isolated from a red seaweed, Grateloupia indica (family: Grateloupiaceae), and has been found to possess a strong blood anti-coagulant activity.

Physicochemical characterization of biosurfactant and its potential to remove oil from soil and cotton cloth

An alkaliphilic bacterium, Klebsiella sp. strain RJ-03, produced a biosurfactant, which showed low viscosity with pseudoplastic rheological behavior and exhibited emulsification activity with oils and hydrocarbons. The biosurfactant has excellent oil removing efficiency as compared to chemical surfactants. The isolated biosurfactant has compatibility with detergents and enhanced oil removing efficiency from soil and cotton cloths. It comprised of sugar, uronic acid, protein and sulfate. GC-MS analysis confirmed the presence of six monosaccharides (w/w), glucose (6.65%), galactose (23.98%), rhamnose (14.94%), mannose (17.54%), fucose (9.47%) and 6-O-Me-galactose (1.4%). It is a high molecular weight, thermostable biopolymer showing degradation above 300 °C. Positive ion reflector mode of MALDI TOF-TOF MS analysis revealed series of low and mid range mass peaks (m/z) corresponding to mono-, di-, tri- and oligo-saccharides content. The NMR, FT-IR, EDX-SEM, AFM and PSD analysis confirmed the presence of functional groups, bonds, elements and particle size respectively.

Purification and characterization of κ-carrageenase from a novel γ-proteobacterium,Pseudomonas elongata (MTCC 5261) syn.Microbulbifer elongatus comb. Nov.

The phenotypic and carrageenolytic features of a novel halo tolerant marine bacterium, isolated from decayed red algal samples collected along the west coast of India were studied. This gram-negative strain was identified asPseudomonas elongala (MTCC 5261) syn.Microbulbifer elongalus comb. nov according to its morphological, physiological and molecular characterization. The extracellular κ-carrageenase was purified 106.54-fold by a combination of ammonium sulfate precipitation (40∼60%) and successive gel filtration chromatography. The purified protein fraction yielded significantly high activity of 426.19 units/mg protein and migrated as a single band on a sodium dodecyl sulfate polyacrylamide gel electrophoresis with a molecular weight of ∼128 kDa. For κ-carrageenase activity, optimum temperature was 40°C whereas two pH optimai.e. 5.6 and 7.7 were observed. For κ-carrageenan, the enzyme gave aKm value of 6.66 mg/mL and aVmax value of 4 μmol/min/mg when the reaction was carried out at 40°C and pH 5.6. Isolated κ-carrageenase could successfully generate protoplasts ofKappaphycus alvarezii. This is the first report on the production of κ-carrageenase by this bacterium isolated from west coast of India. Molecular mass and various characteristics showed that the carrageenase fromP. elongata was much different from those previously reported.

Production and structural characterization of biosurfactant produced by an alkaliphilic bacterium, Klebsiella sp.: evaluation of different carbon sources.

The potential of an alkaliphilic bacterium Klebsiella sp. strain RJ-03, to utilize different carbon sources for the production of an extracellular biosurfactant was evaluated. Among the several carbon substrates tested, production of the crude biosurfactant was found to be the highest with starch (10.1±0.11g/L) followed by sucrose (5.1±0.11g/L), xylose (3.25±0.08g/L), galactose (3.1±0.16g/L) glucose (2.75±0.11g/L) and fructose (2.62±0.07g/L). The crude biosurfactant production was done using starch, sucrose, xylose, galactose and glucose containing medium, that exhibited significantly high viscosity, emulsification activity and maximum reduction in surface tension as compared to those obtained from fructose and maltose. The carbon source has significant effect on the quantity as well as the quality of biosurfactant production. The chemical characteristics of purified biosurfactant was compared by NMR, FT-IR, SEM, GPC, MALDI TOF-TOF MS, GC-MS, TG and DSC analysis, indicating variation in the functional groups, bonds, elements, monosaccharide composition, molecular mass and thermo stability.

Effect of unconventional carbon sources on biosurfactant production and its application in bioremediation.

The potential of an alkaliphilic bacterium Klebsiella sp. strain RJ-03, to utilize different unconventional carbon sources for the production of biosurfactant was evaluated. The biosurfactant produced using corn powder, potato peel powder, Madhuca indica and sugarcane bagasse containing medium, exhibited significantly higher viscosity and maximum reduction in surface tension as compared to other substrates. Among several carbon substrates tested, production of biosurfactant was found to be the highest with corn powder (15.40 ± 0.21 g/l) as compared to others. The comparative chemical characterization of purified biosurfactant was done using advance analytical tools such as NMR, FT-IR, SEM, GPC, MALDI TOF-TOF MS, GC-MS, TG and DSC. Analyses indicated variation in the functional groups, monosaccharide composition, molecular mass, thermostability. Higher yield with cheaper raw materials, noteworthy stress tolerance of CP-biosurfactant toward pH and salt as well as compatibility with chemical surfactants and detergents revealed its potential for commercialization and application in bioremediation.

Hg(II) Removal from Aqueous Solution by Dead Fungal Biomass of Marine Aspergillus niger: Kinetic Studies

Abstract Mercury removal from wastewater is a recognized pollution control challenge today. In the present investigation, the biosorption of Hg(II) onto the dead biomass of four different species of marine Aspergillus, prepared by alkaline treatment, was studied. Among the cultures studied, A. niger was found to be the most efficient for Hg(II) removal. The effects of initial Hg(II) concentration, contact time, pH, temperature, and biosorbent dosage on biosorption were also investigated. It was observed that biosorption equilibriums were established in about 2 h. Under the optimum conditions (pH: 3.0, Hg(II) concentration: 250 mg/L, biomass dose: 0.8 g/L, temperature: 40°C and contact time: 2 h), 40.53 mg Hg(II) was biosorbed per gram of dead biomass of A. niger. Kinetic studies based on fractional power, zero order, first order, pseudo first order, Elovich, second order, and second order rate expressions have also been carried out where the pseudo second order model exhibited best fit to experimental data. The intra‐particle diffusion study revealed that film diffusion is the rate‐limiting sorption process for Hg(II) on A. niger. The nature of the possible cell–metal ion interactions was evaluated by FTIR, SEM, and EDAX analysis. These examinations indicated the involvement of ‐OH and ‐NH2 + groups in the biosorption process present on the surface of the dead fungal biomass. Here, Hg(II) ions were deposited on the surface of the biomass as a film like structure.

Biological neutralization and biosorption of dyes of alkaline textile industry wastewater

The present work was aimed to secure biological neutralization and biosorption of dyes of an alkaline textile industrial effluent (ATIE) using an alkaliphilic bacterium, Enterococcus faecalis strain R-16 isolated from Gujarat coast. The isolate was capable and competent to bring down the pH of ATIE from 12.1 to 7.0 within 2 h in the presence of carbon and nitrogen sources. Carboxylic group concentration (CGC), NMR and FT-IR analysis revealed production of carboxylic acid as a result of neutralization. The unconventional carbon and nitrogen sources like Madhuca indica flowers or sugar cane bagasse supported the growth of bacterium with effective neutralization and biosorption of dyes from ATIE. The process proved to be efficient, inexpensive and eco-friendly as compared to conventional chemical neutralization process.

Bacterial Community Structure in a Semi-Arid Haloalkaline Soil Using Culture Independent Method

Bacterial community structures in two physicochemically different soils from the coastal region of Gujarat, India were investigated using PCR, 16S rRNA gene clone libraries and sequencing methods. The aim of the study was to determine the diversity of bacterial communities inhabiting haloalkaline soil from a semi-arid coastal region. The phylogenetic diversity of bacteria in a haloalkaline soil (EC 20 dS/m; pH 9.5) was compared with a normal soil (EC 0.93 dS/m; pH 7.2). Clones representing phyla Proteobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Actinobacteria, Acidobacteria and Planctomycetes were found in both soils. Cyanobacteria, Verrucomicrobia, OP10 and Bacteria incertae sedis were detected in normal soil whereas Nitrospira was found only in haloalkaline soil. The dominant phylum in the haloalkaline soil was Bacteroidetes followed by Proteobacteria whereas normal soil was dominated by Proteobacteria and Actinobacteria. About 82% of the sequences from the haloalkaline library were related to those previously retrieved from various saline, alkaline and oil-natural gas field ecosystems whereas 50% of the sequences from normal soil resembled sequences of bacteria retrieved from agriculture-related habitats viz. agriculture fields, rhizosphere and grasslands. One third of the total sequences from both soil samples showed low BLAST identities (<95%) suggesting that these soils may harbor unique, novel taxa. Further, the correlation analysis revealed negative correlations of Shannon diversity indices and species evenness with salinity (EC) and pH but positive correlations with total carbon and total nitrogen contents of the soil samples. The haloalkaline soil exhibited less bacterial diversity and communities were significantly different from those of normal soil. In this study, the haloalkaline soil from a semi-arid region supports oligotrophic microbes. Supplemental materials are available for this article. Go to the publishers online edition of Geomicrobiology Journal to view the supplemental file.