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Highlights Coelastrella sp. demonstrated strong lipid production potential, especially at pH 7.0 and 0.5% fertilizer concentration. Stress conditions enhanced lipid accumulation, indicating resilience and adaptability for cultivation. The fatty acid profile supports the use of Coelastrella sp. for sustainable biodiesel production.

Microalgae have been known for broad spectrum of ecological and industrial applications. However, continuous mass culturing of microalgae is still a challenging task. In this context, studies on optimization of culturing conditions like photoperiod and light intensity on nutrients consumption are not uncommon. In the present study, we tried to evaluate the effect of different photoperiod (PP) and photosynthetic photon flux intensity (PPFI) on the nutrient consumption and algal growth of Picochlorum maculatum in shrimp culture effluent. The experiment lasted for 15 days at five different PP cycles (24:0, 18:06, 14:10, 10:14 and 6:18 h light:dark) and four PPFI (50, 100, 150 and 200 µmol m-2 s-1) at 28°C temperature. Every five days the samples were analyzed and results showed that the PP of 18 h light and 6 h dark and 150 µmol m-2 s-1 of PPFI favouring the growth of P. maculatum with a maximum nutrients consumption (PO43+ 91%, NO3- 68%, NO2- 64%,NH3+ 77%), maximum growth (0.876±0.001 abs) and biomass production (9.93±0.19 g L-1) with highest yield of 9.2% total lipid. Among the photoperiod and photosynthetic photon flux intensity tested, 18:6 h light:dark and 150 µmol m-2 s-1 showed the highest nutrients removal and algal growth. This study strongly suggests that P. maculatum PSDK01 was a potential candidate for further commercial development in larger scale. [ABSTRACT FROM AUTHOR]

The present study explores the diversity and ecology of freshwater diatom in the Kanyakumari district, Tamilnadu. Six freshwater ponds namely, Thuckalay pond, Eraniel pond, Pampanvilai pond, Villukuri pond, Erachakulam and Thottiyodu pond were selected from Kalkulam Taluk in Kanyakumari district. A total of 27 taxa of 17 genera were recorded from these freshwater ponds. Among the freshwater diatom species, Gomphonema montanum was found to be the predominant species in all stations except St- 2. The correlation analysis between diatom density and physico-chemical parameters revealed a significant positive correlation of diatoms (Nitzschia sp., Navicula sp., Cyclotella meneghiniana and Stauroneis sp) with nitrate, phosphate and lead at sampling statins St- 2 and 6. CCA analysis revealed that the concentration of calcium, chloride, pH, alkalinity, silica, and ammonia were found to favor the occurrence of dominant species such as Cymbella turgiduta, Gomphonema sp., Rhopalodia sp., in St-3 and St-4. Among all ponds, certain parameters like total alkalinity, nitrite, phosphate, sodium, cobalt, potassium perhaps reflect the influence of agricultural waste, sewage waste, or anthropogenic activities. The statistical indices in coherence with the dominance of pollution indicator species such as Nitzschia palea, Melosira granulata and Cyclotella meneghiniana revealed that the stations St-2, 4 and 6 were heavily polluted, whereas St- 1, 3 and 5 were less polluted.

Printed circuit boards contain precious metals. They are produced in large volumes, rendering them an important component of the electronic waste. In view of the heterogeneity of the metals present, reprocessing of electronic waste is a heinous task. The present study focused on leaching of valuable metals from electronic waste printed circuit boards using Aspergillus niger DDNS1. The adaptation phases began at 0.1, 0.5 and 1.0% of fine powder of printed circuit boards with 10% inoculum and were optimized with three effective factors, viz. initial pH, particle size and pulp density, to achieve the maximum simultaneous recovery of the valuable metals. The interactions of these metals were also deciphered using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectrum and atomic absorption spectroscopy. The results indicated that extraction of the precious metals was accomplished mainly through the unique organic acids originating from A. niger DDNS1. The initial pH played an important role in the extraction of the precious metals and the metals precipitate formation. The leaching rate of the metals was generally higher at low powder dosage of printed circuit boards. The toxicity of the printed circuit boards had little effect on two-step bioleaching at the pulp density of 0.1% compared to one-step bioleaching. The two-step bioleaching process was followed under organic acid-forming conditions for the maximum mobilization of metals. Thus, the precious metals from printed circuit boards could be mobilized through fungal bioleaching which promises an important industrial application in recycling of electronic wastes. [ABSTRACT FROM AUTHOR]

The taxonomic characteristics of weeds such as morphology of shoot, leaves, flowers, stem, fruits and seeds were recorded as Gynandropsis pentaphylla, DC, Amarantus spinosus Linn, Cyperus rotundus, Amarantus viridis Linn, Cassia occidentalis, Linn and Echinochilora orygicola. Totally 20 actinobacteria isolates were screened for herbicidal activity against the weed. Among the 20 isolates, only four actinobacterial isolates KA1-3, KA1-4, KA1-7 and KA23A showed significant herbicidal activity against C. rotundus. The herbicidal effect of actinobacterial culture filtrates on germination and seedling growth of C. rotundus was tested. The shoot and root growth of C. rotundus was severely affected when compared to control. The potent actinobacterial isolates KA1-4 and KA1-7 were characterised based on their morphological and molecular phylogenetic property and were identified as Streptomyces sp. The present study concludes that actinobacterial isolates will be used as bioherbicide against C. rotundus. Further studies are required to confirm the activity of actinobacterial isolates against C. rotundus under field conditions. [ABSTRACT FROM AUTHOR]

A total of 82 endophytic bacteria of tomato and chilli was isolated from different locations of tropical Islands of Andaman and Nicobar, India. Based on in vitro screening, 16 bacterial isolates that effectively inhibited Ralstonia solanacearum (a bacterial wilt pathogen) were characterised for their diversity and identified through Microbial Identification System (Biolog). Diversity analysed through BOX-PCR showed low similarity index among the antagonistic bacteria. Based on the in vitro antagonistic activities, the selected isolates were further characterised for siderophore, indole acetic acid production, phosphate solubilisation and other extracellular enzymes; it is found that most of the isolates were positive for these properties. The production of these metabolites may be responsible for the inhibition of the pathogen R. solanacearum. The isolates BECS3, BECS6 and BECS7 showed multiple attributes and demonstrated plant growth promotion properties through tomato- and chilli-based bioassay under greenhouse conditions. These bacterial inoculations were found to result in significant increase in root, shoot and biomass of both tomato and chilli. Hence, these isolates can be further formulated and used for field application. [ABSTRACT FROM PUBLISHER]

One of the major developments in nanotechnology is the production, manipulation, and use of materials ranging in size from less than a micrometer to that of individual atoms in biology. Though nanomaterials may be synthesized by various physical and chemical methods, synthesis is now possible with the use of biological systems. Nanoparticles synthesized using biological resources have excellent antimicrobial activity. In this review, we critically assess the role of biological entities in the synthesis and antimicrobial potential of metal nanoparticles. [ABSTRACT FROM AUTHOR]

A sponge associated hydrocarbon emulsifying marine fungi Aspergillus sp. MSF1 was isolated from the marine sponge Dendrilla nigra. Production of biosurfactant was confirmed with different screening methods including hemolytic activity, oil displacement test, drop collapsing test, and emulsification index. The production was optimized under submerged fermentation conditions. An enhanced biosurfactant production was achieved with pH 7, 30°C, 2% NaCl, 1% MgCl2, 1% asparagine and glucose and yeast extract as carbon and nitrogen sources, respectively. Among the different media, the Sabouraud's dextrose broth showed the highest emulsification activity. The surface active compound was separated using three step differential solvents fractionation and the active fraction was obtained in diethyl ether. Based on the estimation of macromolecules, TLC, FTIR and HPLC analysis, the surface active compound was characterized as rhamnolipid. Emulsification activity of the cell free supematant and different solvent extracts were compared with chemical surfactants including SDS and Tween80. The surface active compound showed potential activity against the pathogenic yeast Candida albicans and Gram negative bacteria. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the antibacterial efficacy of five Indian medicinal plants such as Acalypha indica L. (A. indica), Aerva lanata (L.) Juss. ex Schult. (A. lanata), Clerodendrum inerme (L.) Gaertn., Pergularia daemia (Forsk.) Chiov. and Solanum surattense Burm. f. against opportunistic bacterial pathogens isolated from HIV infected patients for the potential phytoconstituents in plant extracts. Methods: The opportunistic bacterial pathogens such as Escherichia coli (E. coli), Pseudomonas aeruginosa, Salmonella typhi and Serratia marcescens from Gram-negative group and Staphylococcus aureus from Gram-positive group were isolated from HIV infected patients. The antibacterial efficacy of ethanolic extracts of selected medicinal plants was carried out by disc diffusion method. The potential phytoconstituents of medicinal plant extracts were identified by gas chromatography and mass spectrometry (GC–MS) analysis. Results: Among the five medicinal plants tested, A. indica and A. lanata showed the significant antibacterial activity. A. indica showed potential activity against Staphylococcus aureus and E. coli. A. lanata significantly exhibited antibacterial activity against E. coli, Salmonella typhi and Pseudomonas aeruginosa. A total of 19 phytoconstituents were identified in the ethanolic extract of A. indica and A. lanata by GC–MS analysis respectively. Conclusions: The results of the present investigation revealed that A. indica and A. lanata, possessed significant antibacterial activity when compared with the other plant extracts tested. The presence of 3-O-methyl-d-glucose by GC–MS analysis in both A. indica and A. lanata extracts has not been reported elsewhere in the literature and the findings in this study could be the first one to report.

Abstract: In the background that the marine cyanobacteria offer great potentials as source of fine chemicals, pharmaceuticals, biofuels, etc., in the present study the pigment, C-phycoerythrin (C-PE) extracted from the marine cyanobacterium, Phormidium tenue NTDM05 was used to synthesize CdS nanoparticles. The CdS nanoparticles thus synthesized were characterized adopting UV–Visible spectrum, Fourier transform infra-red spectrum, EDAX and transmission electron microscopy. The size of the CdS nanoparticles was found to be about 5nm. Essentially, it was found that the pigment stabilized the CdS nanoparticles. The pigments labeled CdS nanoparticles could be applied as a biolabel. [Copyright &y& Elsevier]

Pioneering of reliable and eco-friendly process for synthesis of metallic nanoparticles biologically is an important step in the field of application of nanobiotechnology. This paper reports the extracellular biosynthesis of silver nanoparticles using marine cyanobacterium, Oscillatoria willei NTDM01 which reduces silver ions and stabilizes the silver nanoparticles by a secreted protein. The silver nitrate solution incubated with washed marine cyanobacteria changed to a yellow color from 72h onwards, indicating the formation of silver nanoparticles. The characteristics of the protein shell at 265nm were observed in Ultra violet spectrum for the silver nanoparticles in solution. While Fourier Transform Infra Red (FTIR) confirmed the presence of a protein shell which are responsible for the nanoparticles biosynthesis. Scanning Electron Microscopy (SEM) studies showed that the formation of agglomerated silver nanoparticles due to the capping agent in the range of 100 - 200nm. EDS spectrum of the silver nanoparticles was confirmed the presence of elemental silver signal in high percentage. Apart from Eco-friendliness and easy availability and low cost cyanobacterial biomass production will be more advantageous when compared to other classes of micro organism. Biosynthesis nanoparticles would have greater commercial viability if the nanoparticles could be synthesized more rapidly in the reaction vessel. [ABSTRACT FROM AUTHOR]

Diatoms are single cell photosynthesizing eukaryotic algae that produce intricately structured cell wall made of nano-patterned silica. The biologically fabricated nanostructures offer substantially different properties related adhesion, tribology, optic and electronic behavior. In this study biosynthesis and characterization of Silicon-Germanium (Si-Ge) oxide nanocomposite in the diatom, Stauroneis sp., by two stage cultivation process. The exponential growth of Stauroneis sp., inoculated with enrichment medium amended with Germanium. The silicon to germanium concentration molar ratio was 1:0.5. Scanning electron microscopic studies reveals that no structural change is observed when germanium concentration is low, the increased concentration of germanium led to structural changes of the diatoms. The Si-Ge oxide nanocomposite was characterized by Electron Microscopy equipped with energy dispersive spectroscopy to evaluate the chemical composition and structural properties of the diatoms. [ABSTRACT FROM AUTHOR]