Monitoring lipids profile, CO2 fixation, and water recyclability for the economic viability of microalgae Chlorella vulgaris cultivation at different initial nitrogen.

The economic viability of microalgae as a bioenergy source depends on many factors. High CO2 fixing rate, improved lipids yield, and minimum water footprint are few key parameters. This study investigates the effect of four initial nitrogen concentrations (1-, 2-, 6- and 10-mM as nitrate) on lipids yield, their classification and composition, CO2 fixation rate, and water quality for further reuse after first cultivation. The initial 6 mM nitrate was found optimum for the growth and overall lipid productivity of Chlorella vulgaris. The maximum quantum efficiency (as Fv/Fm ratio) for algae decreases along with the cell growth profile and depletion of the initial nitrate concentration. CO2 fixation rate increased initially and peaked during exponential growth and then declined for the rest of the cultivation period. A higher CO2 fixation rate was recorded at 6 mM, and an overall fixation rate of CO2 was high at 6 mM. A higher total organic carbon (TOC) is produced in recycled water at a low nitrogen concentration of 1 and 2 mM. TOC changes during the cultivation period and with each reuse of water. Water was recycled twice successfully, while growth was inhibited during the 3rd cycle. Based on all these investigations, 6 mM of initial nitrogen was found optimal at given growth conditions.

Development of direct conversion method for microalgal biodiesel production using wet biomass of Nannochloropsis salina.

In this work, the effects of several factors, such as temperature, reaction time, and solvent and acid quantity on in situ transesterification yield of wet Nannochloropsis salina were investigated. Under equivalent total solvent volume to biomass ratio, pure alcohol showed higher yield compared to alcohol-chloroform solvent. For esterifying 200 mg of wet cells, 2 ml of methanol and 1 ml of ethanol was sufficient to complete in situ transesterification. Under temperatures of 105 °C or higher, 2.5% and 5% concentrations of sulfuric acid was able to successfully convert more than 90% of lipid within 30 min when methanol and ethanol was used as solvents respectively. Also, it was verified that the optimal condition found in small-scale experiments is applicable to larger scale using 2 L scale reactor as well.

Draft Genome Sequence of Halomonas hydrothermalis MTCC 5445, Isolated from the West Coast of India.

We announce here the draft genome sequence of Halomonas hydrothermalis MTCC 5445, a halophilic bacterium of the class Gammaproteobacteria. It was isolated from the sea coast of Aadri, Veraval, Gujarat, India. Its genome contains genes for polyhydroxybutyrate (PHB), a biodegradable polymer that can be used as a substitute for petroleum plastics.

Biosorption of methylene blue by de-oiled algal biomass: equilibrium, kinetics and artificial neural network modelling.

The main objective of the present study is to effectively utilize the de-oiled algal biomass (DAB) to minimize the waste streams from algal biofuel by using it as an adsorbent. Methylene blue (MB) was used as a sorbate for evaluating the potential of DAB as a biosorbent. The DAB was characterized by SEM, FTIR, pHPZC, particle size, pore volume and pore diameter to understand the biosorption mechanism. The equilibrium studies were carried out by variation in different parameters, i.e., pH (2-9), temperature (293.16-323.16 K), biosorbent dosage (1-10 g L(-1)), contact time (0-1,440 min), agitation speed (0-150 rpm) and dye concentration (25-2,500 mg L(-1)). MB removal was greater than 90% in both acidic and basic pH. The optimum result of MB removal was found at 5-7 g L(-1) DAB concentration. DAB removes 86% dye in 5 minutes under static conditions and nearly 100% in 24 hours when agitated at 150 rpm. The highest adsorption capacity was found 139.11 mg g(-1) at 2,000 mg L(-1) initial MB concentration. The process attained equilibrium in 24 hours. It is an endothermic process whose spontaneity increases with temperature. MB biosorption by DAB follows pseudo-second order kinetics. Artificial neural network (ANN) model also validates the experimental dye removal efficiency (R2 = 0.97) corresponding with theoretically predicted values. Sensitivity analysis suggests that temperature and agitation speed affect the process most with 23.62% and 21.08% influence on MB biosorption, respectively. Dye adsorption capacity of DAB in fixed bed column was 107.57 mg g(-1) in preliminary study while it went up to 139.11 mg g(-1) in batch studies. The probable mechanism for biosorption in this study is chemisorptions via surface active charges in the initial phase followed by physical sorption by occupying pores of DAB.

Utilization of lipid extracted algal biomass and sugar factory wastewater for algal growth and lipid enhancement of Ettlia sp.

The present study assessed the use of hydrolysate of lipid extracted algal biomass (LEA) combined with the sugar factory wastewater (SFW) as a low cost nutrient and a carbon source, respectively for microalgal cultivation. Microalgal strain Ettlia sp. was both mixotrophically and heterotrophically cultivated using various amounts of hydrolysate and SFW. The culture which was grown in medium containing 50% LEA hydrolysate showed highest growth, achieving 5.26 ± 0.14 gL(-1) after 12 days of cultivation. The addition of SFW increased the lipid productivity substantially from 5.8 to 95.5 mg L(-1)d(-1) when the culture medium was fortified with 20% SFW. Gas chromatography analysis indicated a noticeable increase of 20% in C16 and C18 fraction in FAME distribution under above condition. Therefore, it can be concluded that the combination of LEA hydrolysate and sugar factory waste water can be a powerful growth medium for economical algal cultivation.

Rapid quantification of microalgal lipids in aqueous medium by a simple colorimetric method.

Identification of novel microalgal strains with high lipid productivity is one of the most important research topics in renewable biofuel research. However, the major bottleneck in the strain screening process is that currently known methods for the estimation of microalgal lipid are laborious and time-consuming. The present study successfully employed sulpho-phospho-vanillin (SPV) colorimetric method for direct quantitative measurement of lipids within liquid microalgal culture. The SPV reacts with lipids to produce a distinct pink color, and its intensity can be quantified using spectrophotometric methods by measuring absorbance at 530nm. This method was employed for a rapid quantification of intracellular lipid contents within Chlorella sp., Monoraphidium sp., Ettlia sp. and Nannochloropsis sp., all of which were found to have lipid contents ranging in between 10% and 30%. Subsequent analysis of the biomass using gas chromatography confirmed that our protocol is highly accurate (R(2)=0.99).

Advances in the applications of polyhydroxyalkanoate nanoparticles for novel drug delivery system.

Drug delivery technology is emerging as an interdisciplinary science aimed at improving human health. The controlled delivery of pharmacologically active agents to the specific site of action at the therapeutically optimal rate and dose regimen has been a major goal in designing drug delivery systems. Over the past few decades, there has been considerable interest in developing biodegradable drug carriers as effective drug delivery systems. Polymeric materials from natural sources play an important role in controlled release of drug at a particular site. Polyhydroxyalkanoates, due to their origin from natural sources, are given attention as candidates for drug delivery materials. Biodegradable and biocompatible polyhydroxyalkanoates are linear polyesters produced by microorganisms under unbalanced growth conditions, which have emerged as potential polymers for use as biomedical materials for drug delivery due to their unique physiochemical and mechanical properties. This review summarizes many of the key findings in the applications of polyhydroxyalkanoates and polyhydroxyalkanoate nanoparticles for drug delivery system.

Recent insights in the removal of Klebseilla pathogenicity factors for the industrial production of 2,3-butanediol.

2,3-Butanediol (2,3-BDO) has immense industrial applications. Recently, microbial fermentation has emerged as an alternative way to produce this industrially important chemical. Although 2,3-BDO is produced by several microorganisms, the Klebsiella genera has an excellent production compared with other 2,3-BDO-producing microorganisms. In order to produce 2,3- BDO on a large scale, the challenges of removing pathogenic factors from Klebsiella pneumoniae need to be addressed. K. pneumoniae produces a number of virulence factors that contribute to its pathogenesis, including lipopolysaccharides, capsules, fimbrial adhesins, etc. Removal of these pathogenic factors from 2,3-BDO-producing Klebsiella strains will result in avirulent strains for the safe, economic, and efficient production of 2,3-BDO. In this review, we summarize the current trends in 2,3-BDO production using K. pneumoniae and insights into the removal of its virulence factors for industrial applications.

Purification and characterization of haloalkaline thermoactive, solvent stable and SDS-induced protease from Bacillus sp.: a potential additive for laundry detergents.

An extracellular haloalkaline, thermoactive, solvent stable, SDS-induced serine protease was purified and characterized from an alkali-thermo tolerant strain Bacillus sp. SM2014 isolated from reverse osmosis reject. The enzyme was purified to homogeneity with recovery of 54.4% and purity fold of 64. The purified enzyme was composed of single polypeptide of molecular mass about 71 kDa. The enzyme showed optimum activity at alkaline pH 10 and temperature 60°C. The km and Vmax for the enzyme was 0.57 mg/ml and 445.23 U/ml respectively. The enzyme showed novel catalytic ability at high pH (10), temperature (60°C) and salinity (3M). Moreover, the stability of enzyme in organic solvents (50% v/v) of logP ≥ 2 signified the prospective of this enzyme for peptide synthesis. The compatibility of the enzyme with surfactants and various detergent matrices together with wash performance test confirmed its potential applicability in laundry industry.

Effect of light quality on the C-phycoerythrin production in marine cyanobacteria Pseudanabaena sp. isolated from Gujarat coast, India.

The isolated cyanobacterium containing biopigments like chlorophyll-a, phycoerythrin, phycocyanin, and carotenoid was cultured under different quality of light modes to ascertain biomass and pigment productivity. On the basis of 16S rRNA gene sequence, the isolate was identified as Pseudanabaena sp. Maximum biomass concentration obtained in white-, blue-, and green-light was 0.82, 0.94, and 0.89 g/L, respectively. It was observed that maximum phycoerythrin production was in green light (39.2 mg/L), ensued by blue light (32.2 mg/L), while phycocyanin production was maximum in red light (10.9 mg/L). In yellow light, pigment production as well as the growth rate gradually declined after 12 days. Carotenoid production decreased in blue-, white-, and red-light after 15 days, while in green light it had increased gradually. The present communication suggests that Pseudanabaena sp. can be used for commercial production of phycoerythrin when grown under green light.

Preparation of highly purified C-phycoerythrin from marine cyanobacterium Pseudanabaena sp.

C-phycoerythrin was isolated and purified from marine Pseudanabaena sp. using two step chromatographic methods. Phycobiliproteins in the marine Pseudanabaena was extracted in 100 mM phosphate buffer (pH 7.2) and precipitated by salting out. The precipitated C-phycoerythrin was purified by gel filtration with Sephadex G-150, and then it was purified by ion exchange chromatography on DEAE cellulose, which was developed by linear ionic strength gradients. Purified phycoerythrin showed absorption maxima at 568 and 541 nm, and displayed a fluorescence maximum at 578 nm. The absorbance ratio A568/A280, a criterion for purity (purity ratio) achieved was 6.86. It showed a single band on examination by polyacrylamide gel electrophoresis (PAGE). The polypeptide analysis of the purified C-phycoerythrin by SDS-PAGE demonstrated that it contained two chromophore-carrying subunits. The yield of purified C-phycoerythrin obtained was 13.6 mg/g of the cell dry weight with 47% of yield. Obtaining highly pure C-phycoerythrin allows one to evaluate its fluorescence properties for future applications in biochemical and biomedical research.

Zn(II)-cyclam based chromogenic sensors for recognition of ATP in aqueous solution under physiological conditions and their application as viable staining agents for microorganism.

Two chromogenic complexes, L.Zn (where L is (E)-4-((4-(1,4,8,11-tetraazacyclotetradecan-1-ylsulfonyl)phenyl)diazenyl)-N,N-dimethylaniline) and its [2]pseudorotaxane form (α-CD.L.Zn), were found to bind preferentially to adenosine triphosphate (ATP), among all other common anions and biologically important phosphate (AMP, ADP, pyrophosphate, and phosphate) ions in aqueous HEPES buffer medium of pH 7.2. Studies with live cell cultures of prokaryotic microbes revealed that binding of these two reagents to intercellular ATP, produced in situ, could be used in delineating the gram-positive and the gram-negative bacteria. More importantly, these dyes were found to be nontoxic to living microbes (eukaryotes and prokaryotes) and could be used for studying the cell growth dynamics. Binding to these two viable staining agents to intercellular ATP was also confirmed by spectroscopic studies on cell growth in the presence of different respiratory inhibitors that influence the intercellular ATP generation.

Zn(II) based colorimetric sensor for ATP and its use as a viable staining agent in pure aqueous media of pH 7.2.

Selective colorimetric detection of ATP in physiological conditions by a Zn(II)-based receptor is reported. This reagent was found to be non-toxic to the living cells and could be used for studying the growth of the yeast cells.

Effect of preservatives for food grade C-Phycoerythrin, isolated from marine cyanobacteria Pseudanabaena sp.

C-Phycoerythrin is water soluble red color chromo-protein, which is used as a natural food colorant. The effect of selected edible preservatives like citric acid, sodium chloride, sucrose and calcium chloride on the stability of C-Phycoerythrin at 0±5°C and 35±5°C was studied in aqueous solution. Experiment was carried out to select a stabilizing agent having Hofmeister series behavior acting on hydrophobic interactions. The denaturation of phycoerythrin with urea as denaturant and effect of different pH on C-Phycoerythrin was studied. Citric acid (4 mg/ml) was observed to be one of the best preservative for C-Phycoerythrin at 35±5°C and 0±5°C in aqueous solution for 45 days. Citric acid was able to maintain the stability of C-Phycoerythrin in the solution. The amount of C-Phycoerythrin left in the solution containing citric acid after 30 and 45 days was 46 and 37.8% respectively at higher temperature.

Isolation of promising bacterial strains from soil and marine environment for polyhydroxyalkanoates (PHAs) production utilizing Jatropha biodiesel byproduct.

PHAs are biodegradable and environmentally friendly thermoplastics. The major contributor to PHA production cost is carbon substrate cost, therefore it is desirable to produce PHA from waste/byproducts like Jatropha biodiesel byproducts. This study was done using Jatropha biodiesel byproduct as carbon source, to decrease production cost for PHAs. Total 41 isolates from soil and marine source were able to utilize Jatropha biodiesel byproduct. Nine bacteria were selected for further studies, which were found positive for Nile red viable colony screening. Two bacterial isolates SM-P-1S and SM-P-3M isolated from soil and marine environment respectively, were found promising for PHA production. PHA accumulation for SM-P-1S and SM-P-3M was 71.8% and 75% PHA/CDW respectively and identified as Bacillus sonorensis and Halomonas hydrothermalis by MTCC. The PHA obtained from SM-P-1S and SM-P-3M was analyzed by FTIR and NMR as polyhydroxybutyrate (PHB).

A thermoactive alpha-amylase from a Bacillus sp. isolated from CSMCRI salt farm.

Amylases are the most important hydrolytic enzymes for starch-based industries. It is desirable that alpha-amylases should be active at high temperature of gelatinization (100-110 degrees C) and liquefaction (80-90 degrees C) to economize processes. Therefore, thermostable and thermoactive enzyme from natural bacterial strain would have wide industrial importance. In the present study a highly thermoactive and thermostable amylase producing Bacillus sp. was isolated from experimental salt farm of Central Salt and Marine Chemicals Research Institute, yielding 452Uml(-1) amylase in medium containing (%) NaCl 0.5, peptone 0.5, beef extract 0.3, starch 1.0 at 37 degrees C, pH 7.0 after 48h of incubation. Maximum activity of amylase was observed at pH 8.0 and 110 degrees C temperature. The crude enzyme was highly active between pH 6.0 and 11.0 and observed to be active and thermostable after 30min of incubation at 60 degrees C. These properties indicated that the isolated alpha-amylase enzyme is suitable for starch liquefaction and other food processing.

Polyhydroxyalkanoate (PHA) synthesis by Spirulina subsalsa from Gujarat coast of India.

Cyanobacteria have many unexploited potential for natural products with a huge variability in structure and biological activity. Their products are species specific and substrate+growth condition specific. Under stress conditions they are reported to produce biopolymers like EPS and PHA, which can be produced extracellularly and intracellularly, respectively. Polyhydroxyalkanoates are polymers of biological origin, they are also capable of being completely broken down to water and carbon dioxide by microorganisms found in a wide range of environments, such as soil, water, and sewage. We have studied marine cyanobacteria Spirulina subsalsa from Veraval coast, Gujarat, India, producing PHA under increased sodium chloride (NaCl) concentration (5% enhancement to the ASNIII medium), The biopolymer was chemically characterized through FTIR, NMR, TGA, and DSC. The present study shows increased PHA accumulation in S. subsalsa by twofold increased NaCl concentration in the growth media.

Resonance energy transfer approach and a new ratiometric probe for Hg2+ in aqueous media and living organism.

Resonance energy transfer from dansyl to the rhodamine moiety in a newly synthesized chemosensor L(2) has been utilized successfully for detection of Hg(2+) in aqueous solution and living cells such as Pseudomonas putida.

Colorimetric sensor for triphosphates and their application as a viable staining agent for prokaryotes and eukaryotes.

The chromogenic complex 1 x Zn (where 1 is (E)-4-(4-dimethylamino-phenylazo)-N,N-bispyridin-2-ylmethyl-benzenesulfonamide) showed high affinity toward the phosphate ion in tetrabutylammonium phosphate in acetonitrile solution and could preferentially bind to adenosine triphosphate (ATP) in aqueous solution at physiological pH. This binding caused a visual change in color, whereas no such change was noticed with other related anions (adenosine monophosphate, adenosine diphosphate, pyrophosphate, and phosphate) of biological significance. Thus, 1 x Zn could be used as a staining agent for different biological cells through binding to the ATP, generated in situ by the mitochondria (in eukaryotes). For prokaryotes (bacteria) the cell membrane takes care of the cells' energy conversion, since they lack mitochondria. ATP is produced in their unique cell structure on the cell membrane, which is not found in any eukaryotes. These stained cells could be viewed with normal light microscopy. This reagent could even be used for distinguishing the gram-positive and the gram-negative bacteria (prokaryotes). This dye was found to be nonlipophilic in nature and nontoxic to living microbes (eukaryotes and prokaryotes). Further, stained cells were found to grow in their respective media, and this confirmed the maintenance of viability of the microbes even after staining, unlike with many other dyes available commercially.

A rhodamine-based chemosensor that works in the biological system.

A new rhodamine-based reversible chemosensor (L1 ) is reported, which could bind Hg2+ and Cu2+ in aqueous methanol solution with detectable change in color. Cu2+ and Hg2+ ions responded differently toward the fluorescence output signals on binding to L1.L1 could also be used as a selective probe for monitoring Hg2+ adsorbed on bacteria using an optical microscope.