Showing papers in "Biotechnology & Biotechnological Equipment in 2015"
TL;DR: Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes, to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies.
Abstract: The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies.
988 citations
TL;DR: This review critically assesses the role of fungi in the synthesis of nanoparticles, the mechanism involved in the synthesisation, the effect of different factors on the reduction of metal ions in developing low-cost techniques for the synthesis and recovery of nanoparticle.
Abstract: Nanotechnology can offer green and eco-friendly alternatives for plant disease management. Apart from being eco-friendly, fungi are used as bio-manufacturing units, which will provide an added benefit in being easy to use, as compared to other microbes. The non-pathogenic nature of some fungal species in combination with the simplicity of production and handling will improve the mass production of silver nanoparticles. Recently, a diverse range of fungi have been screened for their ability to create silver nanoparticles. Mycosynthesis of gold, silver, gold-silver alloy, selenium, tellurium, platinum, palladium, silica, titania, zirconia, quantum dots, usnic acid, magnetite, cadmium telluride and uraninite nanoparticles has also been reported by various researchers. Nanotechnological application in plant pathology is still in the early stages. For example, nanofungicides, nanopesticides and nanoherbicides are being used extensively in agriculture practices. Remote activation and monitoring of intelligent nano-delivery systems can assist agricultural growers of the future to minimize fungicides and pesticides use. Nanoparticle-mediated gene transfer would be useful for improvement of crops resistant to pathogens and pest. This review critically assesses the role of fungi in the synthesis of nanoparticles, the mechanism involved in the synthesis, the effect of different factors on the reduction of metal ions in developing low-cost techniques for the synthesis and recovery of nanoparticles. Moreover, the application of nanoparticles in plant disease control, antimicrobial mechanisms, and nanotoxicity on plant ecosystem and soil microbial communities has also been discussed in detail.
256 citations
TL;DR: This paper reviews recent literature on some examples of variety/ line development using MABC strategy in rice growing countries through MABC within the shortest timeframe.
Abstract: The world's population is increasing very rapidly, reducing the cultivable land of rice, decreasing table water, emerging new diseases and pests, and the climate changes are major issues that must be addressed to researchers to develop sustainable crop varieties with resistance to biotic and abiotic stresses. However, recent scientific discoveries and advances particularly in genetics, genomics and crop physiology have opened up new opportunities to reduce the impact of these stresses which would have been difficult if not impossible as recently as the turn of the century. Marker assisted backcrossing (MABC) is one of the most promising approaches is the use of molecular markers to identify and select genes controlling resistance to those factors. Regarding this, MABC can contribute to develop resistant or high-yielding or quality rice varieties by incorporating a gene of interest into an elite variety which is already well adapted by the farmers. MABC is newly developed efficient tool by which using large population sizes (400 or more plants) for the backcross F1 generations, it is possible to recover the recurrent parent genotype using only two or three backcrosses. So far, many high yielding, biotic and abiotic stresses tolerance, quality and fragrance rice varieties have been developed in rice growing countries through MABC within the shortest timeframe. Nowadays, MABC is being used widely in plant breeding programmes to develop new variety/lines especially in rice. This paper reviews recent literature on some examples of variety/ line development using MABC strategy.
148 citations
TL;DR: The antimicrobially active strains do not cause concerns about antibiotic resistance transfer and could be used as natural biopreservatives in food and therapeutic formulations.
Abstract: Antimicrobial activity and antibiotic susceptibility were tested for 23 Lactobacillus and three Bifidobacterium strains isolated from different ecological niches. Agar-well diffusion method was used to test the antagonistic effect (against Staphylococcus aureus, Escherichia coli, Bacillus cereus and Candida albicans) of acid and neutralized (pH 5.5) lyophilized concentrated supernatants (cell-free supernatant; CFS) and whey (cell-free whey fractions; CFW) from de Man–Rogosa–Sharpe/trypticase-phytone-yeast broth and skim milk. Acid CFS and CFW showed high acidification rate-dependent bacterial inhibition; five strains were active against C. albicans. Neutralized CFS/CFW assays showed six strains active against S. aureus (L. acidophilus L-1, L. brevis 1, L. fermentum 1, B. animalis subsp. lactis L-3), E. coli (L. bulgaricus 6) or B. cereus (L. plantarum 24-4В). Inhibition of two pathogens with neutralized CFS (L. bulgaricus 6, L. helveticus 3, L. plantarum 24-2L, L. fermentum 1)/CFW (L. plantarum 24-5D, L. ...
142 citations
TL;DR: A newly isolated bacterium identified as Bacillus safensis based on biochemical tests and 16S rRNA analysis and its mutant variant created by exposure to ultraviolet radiation at 254 nm were investigated for keratinolytic activity as mentioned in this paper.
Abstract: A newly isolated bacterium identified as Bacillus safensis based on biochemical tests and 16S rRNA analysis and its mutant variant created by exposure to ultraviolet radiation at 254 nm were investigated for keratinolytic activity. The wild-type strain produced 35.4–50.4 U/mL keratinase over a period of 120 h, while the mutant one yielded 64.4–108.5 U/mL keratinase for the same period of 120 h. The optimal conditions for the enzyme activities were pH 7.5 and 40 °C. The mutant and wild-type strain keratinases retained 59% and 54% of their activity after 12 h pretreatment at 40 °C, and 64% and 60% of their activity after 12 h at pH 7.5, respectively. The keratinases showed high substrate specificity for feathers, but low specificity for human and bovine hairs. The enzymes were activated by Na+, Ca2+, Fe2+ and Mg2+. However, while Mn2+ activated the enzyme from the mutant strain, it inhibited that of the wild type. The mutant and wild-type strain completely degraded whole chicken feathers after 6 and 9 days ...
70 citations
TL;DR: In this article, the authors developed an efficient, easily reproducible and environmentally friendly method for biosynthesis of cadmium sulphide quantum dots based on the usage of mycelium of the basidiomycete fungus Pleurotus ostreatus.
Abstract: The development of ‘green’ technologies in nanoparticle synthesis is of considerable importance to broaden their biological applications. Cadmium sulphide nanoparticles are considered very promising in applied chemistry, bioscience and medicine. The aim of this study was to develop an efficient, easily reproducible and environmentally friendly method for biosynthesis of cadmium sulphide quantum dots based on the usage of mycelium of the basidiomycete fungus Pleurotus ostreatus. By incubating P. ostreatus mycelium with inorganic cadmium sulphate and sodium sulphide, we synthesized stable luminescent CdS nanocrystals. They showed absorption peaks at 453 nm (ultraviolet–visible spectrometry) and a main luminescent peak at 462 nm. Transmission electron microscopy revealed that the obtained quantum dots were of a spherical shape and predominantly from 4 to 5 nm in size. The electron diffraction pattern confirmed the wurtzite crystalline structure of the synthesized cadmium sulphide quantum dots. The obtained r...
67 citations
TL;DR: It is elucidates that strain Pseudomonas aeruginosa (IES-Ps-1) is a versatile toxic organic compound degrader and with the degradation of malathion and cypermethrin, this strain was able to degrade phenol.
Abstract: This article elucidates that strain Pseudomonas aeruginosa (IES-Ps-1) is a versatile toxic organic compound degrader. With the degradation of malathion and cypermethrin (studied by other researchers previously), this strain was able to degrade phenol. Two other indigenous soil flora (i.e., Pseudomonas sp. (IES-S) and Bacillus subtilis (IES-B)) were also found to be potential phenol degraders.Phenol was degraded with Monod kinetics during growth in nutrient broth and mineral salts medium. Before entering into the growth inhibition phase, strains IES-Ps-1, IES-S and IES-B could tolerate up to 400, 700 and 500 mg/L phenol, respectively, when contained in nutrient broth. However, according to the Luong–Levenspiel model, the growth of strains IES-Ps-1, IES-S and IES-B would cease at 2000, 2174 and 2190 mg/L phenol, respectively. Strain IES-Ps-1 degraded 700, 900 and 1050 mg/L phenol contained in mineral salts medium with the specific rates of 0.034, 0.075 and 0.021 h−1, respectively. All these strains grew by ...
62 citations
TL;DR: The fatty acid profiles of the oil for the cultures met the necessary requirements and the strains are promising resources for biofuel production.
Abstract: The growth of the algae Chlorella vulgaris, Botryococcus braunii and Scenedesmus sp. under mixotrophic conditions in the presence of different concentrations of crude glycerol was evaluated with the objective of increasing the biomass growth and algal oil content. A high biomass concentration was characteristic of these strains when grown on crude glycerol compared to autotrophic growth, and 5 g/L glycerol yielded the highest biomass concentration for these strains. Mixotrophic conditions improved both the growth of the microalgae and the accumulation of triacylglycerols (TAGs). The maximum amount of TAGs in the algae biomass was obtained in the 5 g/L glycerol growth medium. The fatty acid profiles of the oil for the cultures met the necessary requirements and the strains are promising resources for biofuel production.
53 citations
TL;DR: Nodal and leaf derived calli differentiated into shoot promordia when subcultured on MS media supplemented with different concentration of BAP, kinetin and thidiazuran as well as gibberellic acid (GA3) and NAA.
Abstract: The present study investigated the effect of various concentrations and combinations of plant growth regulators on callus induction, shoot proliferation and root regeneration of three potato (Solanum tuberosum L.) cultivars by using potato nodal and leaf explants under long-day conditions. The minimum days for callus induction (8.33 d), the maximum callus formation percentage (87.50%), the largest callus diameter (1.90 cm) and the maximum callus weight (2.04 g) were recorded on 1.0 × Murashige and Skoog (MS) medium containing 3.0 mg L−1 benzyl amino purine (BAP) + 2.0 mg L−1 naphthalene acedic acid (NAA). Nodal explants demonstrated a better performance for callus induction compared to leaf segments. Nodal and leaf derived calli differentiated into shoot promordia when subcultured on MS media supplemented with different concentration of BAP, kinetin and thidiazuran as well as gibberellic acid (GA3) and NAA. The maximum shoot regeneration percentage (90.00%) and the maximum number of shoots (6.42) were obt...
45 citations
TL;DR: In this article, the authors used Artificial Neural Networks (ANNs) for the modelling of bio-hydrogen yield in microbial electrolysis cells (MECs) by using a committee of five ANNs.
Abstract: The enhancement of hydrogen yield in microbial electrolysis cells (MECs) requires a robust process model that accurately relates the effect of anodic physicochemical input variables to the process output. Artificial neural networks (ANNs) have been used for the modelling of complex and non-linear processes. This paper reports the modelling of biohydrogen yield in MECs by using a committee of five ANNs. A topology of 6–(6, 8, 11, 12, 14)–1 was adopted, corresponding to the number of neurons of inputs, hidden (varied) and output layers. The ANN inputs were substrate type, substrate concentration, pH, temperature, applied voltage and reactor configuration. Model development was carried out with 50 data points from 15 published studies. The coefficients of determination (R2) between the experimental and predicted hydrogen yields for the five models were as follows: 0.90, 0.81, 0.85, 0.70 and 0.80. Model validation on new MEC processes showed a strong correlation between the observed and predicted hydrogen yie...
44 citations
TL;DR: Investigating the hepatoprotective effects of a polysaccharide isolated from D. huoshanense revealed that it was partly attributed to its anti-inflammatory action.
Abstract: Dendrobium huoshanense is a precious herbal medicine in China, which exhibits a variety of restorative and therapeutic effects. This study aimed at investigating the hepatoprotective effects of a polysaccharide (DHP1A) isolated from D. huoshanense via water extraction, diethylaminoethyl (DEAE) cellulose anion exchange and size exclusion chromatography. The animal experiment indicated that the oral administration of DHP1A obviously reduced the levels of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and 8-hydroxy-2′-deoxyguanosine in the serum of mice treated with carbon tetrachloride (CCl4), suggesting the hepatoprotective potential of this polysaccharide. Moreover, DHP1A decreased the expressions of tumor necrosis factor-α, interleukin-1β, monocyte chemoattractant protein-1, macrophage inflammatory protein-2, CD68 and phosphorylated IκBα (p-IκBα) in the CCl4-treated mice. These results revealed that the hepatoprotective effect of DHP1A was partly attributed to its anti-inflammatory action.
TL;DR: In this article, the authors present measurements and analysis of temperatures in ultrasonically assisted drilling of bone and find critical drilling parameters (drill speed and feed rate) and ultrasonic parameters (frequency and amplitude) for producing higher temperatures.
Abstract: Heat generation is a well-known problem in bone drilling. Excessive heat generation during drilling operation on bone causes necrosis of the tissue. This paper presents measurements and analysis of temperatures in ultrasonically assisted drilling of bone. The main objective was to find critical drilling parameters (drill speed and feed rate) and ultrasonic parameters (frequency and amplitude) for producing higher temperatures in bone. The increase in drilling speed and feed rate were found to increase the temperatures in bone. The frequencies above 15 kHz were found to produce higher temperatures in bone. The feed rates above 30 mm/min and the amplitude of vibration up to 20 µm were found to have no significant effect on bone temperature. Ultrasonically assisted drilling may be used as an alternative to conventional drilling in orthopaedic surgical procedures to avoid death of bone cells.
TL;DR: In this article, the authors evaluated in vitro antioxidant potential of 14 medicinal plants, 8 of which are endemic species of Anatolia, and obtained significant differences in the antioxidant potential amongst the tested methanolic plant extracts.
Abstract: The aim of our study was to evaluate in vitro antioxidant potential of methanolic extracts (ME) of 14 medicinal plants, 8 of which are endemic species of Anatolia. Scavenging activity was tested by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and the inhibitory effect on lipid peroxidation was examined by the ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods. The obtained results showed significant differences in the antioxidant potential amongst the tested methanolic plant extracts. Among the plant samples, Crataegus microphylla C. Koch, Salvia hypargeia Fisch. & Mey., Cotinus coggygria Scop., Origanum sipyleum L. and Rosa damascena Miller exhibited the highest DPPH scavenging activity. Five extracts (Centaurea nerimaniae S. Kultur, C. coggygria, Scorzonera tomentosa L., R. damascena and Colchicum sanguicolle K.M. Perss) showed strong antioxidant activity in the FTC and TBA tests, with per cent inhibition ranges of 72%–84% and 84%–92%, respectively. The ME of C. coggygria and R. damascena exh...
TL;DR: Additional evidence is provided regarding the influence of different LEDs on ginsenoside production applying high-performance liquid chromatography (HPLC) analysis with photo-diode array (PDA) detection at ultraviolet (UV) wavelength 203 nm.
Abstract: In recent years, LED (light-emitting diode) has been the subject of research within the field of plant growth and development. However, there has been little discussion about using LED in vitro cultures of Panax vietnamensis, one of the important medicinal plants belonging to the Panax genus. This study examines the influence of various LED lamps on callus growth and plant formation of P. vietnamensis. Results show significant differences in growth and development, as various light conditions were suitable for different stages. Callus of 70 mg in fresh weight cultured under yellow LEDs resulted in growth of 1197 mg in fresh weight and 91.7 mg of dry weight, within a period of three months. The most effective plant formation was obtained when embryogenic calli were cultured under the combination of 60% red LED and 40% blue LED with an average of 11.21 plantlets per explant; the shoot clump fresh weight and dry weight were of 1147 and 127 mg, respectively, and the average plant height was 3.1 cm. It was also shown that this light condition was the most efficient for P. vietnamensis in vitro plant growth and development. This study provided additional evidence regarding the influence of different LEDs on ginsenoside production applying high-performance liquid chromatography (HPLC) analysis with photo-diode array (PDA) detection at ultraviolet (UV) wavelength 203 nm. The highest MR2 content was recorded when plants maintained under 20% red LED combined with 80% blue LED. However, the highest Rg1 and Rb1 content was found under fluorescent light. The results presented might provide new strategies using LEDs for adequate micropropagation protocols of P. vietnamensis.
TL;DR: Results indicated that eggshells, as a biopolymer, are a promising flocculant due to their high separation efficiency, low dose requirements and short mixing and settling time.
Abstract: The aim of this study was to determine the optimal conditions for adding eggshells as a bioflocculant (including concentration dosage, pH, mixing time, mixing rate and settling time) in harvesting Chlorella vulgaris cells from liquid cultures, using the well-known jar-test experimental method Eggshells separated successfully 99 ± 04% of the C vulgaris biomass at the following optimal parameters: eggshell concentration 80 mg/L, mixing time 20 min, mixing rate 150 r/min and settling time 20 min at pH 6 These results indicated that eggshells, as a biopolymer, are a promising flocculant due to their high separation efficiency, low dose requirements and short mixing and settling time Eggshells not only act as an adsorbent, but also spontaneously coagulate to agglomerate the microalgae cells
TL;DR: High prevalence of vitamin D insufficiency after kidney transplantation in the studied cohort of patients was demonstrated and serum 25(OH)D was found to be inversely associated with calcineurin inhibitors (CNI) and unaffected by other immunosuppressive agents.
Abstract: There is a growing body of evidence for the protective role of vitamin D in diabetes mellitus (DM), infection, cancer, cardiovascular disease, immune disorders and kidney function. Considering the reported high prevalence of vitamin D insufficiency among kidney transplant recipients (KTRs), the aim of this study was to assess the influence of immunosuppressive therapy and other factors on vitamin D status in such patients. The study included 289 KTRs (189 males and 100 females) who consented to participate. The first test for 25-hydrohyvitamin D [25(OH)D] was performed by a validated liquid chromatography–tandem mass spectrometry method. Influence of immunosuppressive drugs and previously reported predictors on vitamin D status was assessed by descriptive statistics, univariate and multivariate regression. Our results showed that only 53 patients (18.34%) of the studied KTRs were vitamin D sufficient. In addition to a well expected positive association between serum 25(OH)D and summer blood sampling (p < 0.05) and inverse relationship between vitamin D status and DM, gender (female) and body mass index, serum 25(OH)D was found to be inversely associated with calcineurin inhibitors (CNI) (p < 0.05) and unaffected by other immunosuppressive agents. Our study demonstrated high prevalence of vitamin D insufficiency after kidney transplantation in the studied cohort of patients. Apart from female gender, winter months, DM and overweight, the use of CNI could be considered an additional significant predictor of lower 25(OH)D in Bulgarian KTRs.
TL;DR: Results indicated that an approximately 1.5%–20% concentration of the bacteria-free filtrate, could effectively inhibit hyphae growth and bacterial suppression of germ tubes and mycelium growth was observed, rather than lysis.
Abstract: Strain L2 (a Bacillus megaterium species that was isolated from tobacco's rhizosphere) was applied to inhibit the pathogen Alternaria alternata in an attempt to reduce tobacco brown spot disease. This study focused on inhibition experiments, in which culture filtrate inhibited A. alternata’s mycelium growth, its spore germination rate and its spore output. The results indicated that an approximately 1.5%–20% concentration of the bacteria-free filtrate, could effectively inhibit hyphae growth. Additionally, bacterial suppression of germ tubes and mycelium growth was observed, rather than lysis. Furthermore, the filtrate caused some of the germinal tubes to undergo vacuolization and even rupturing. The inhibitory effect was associated with the change of the concentration: the greater the concentration, the greater the impact on A. alternata.
TL;DR: The preliminary screening assay indicated that some of the Turkish plants with antibacterial properties may offer alternative therapeutic agents against bacterial infections in aquaculture industry.
Abstract: The antibacterial activity of ethanolic and aqueous crude extracts from 36 plants in Turkey, including seven endemic species, against fish pathogens was studied using the disc diffusion assay. The extract that was most active against all microbial strains, except Aeromonas salmonicida, was that of Dorycnium pentaphyllum. Some of the extracts also showed a very broad spectrum of potent antimicrobial activity. The extract of Anemone nemorosa showed the highest antimicrobial activity against Vibrio anguillarum. V. anguillarum, a Gram-negative bacterium, appeared to be the most susceptible to the plant extracts used in this experiment. To the best of our knowledge, this is the first report on the antimicrobial activity of 11 of the studied plants. The preliminary screening assay indicated that some of the Turkish plants with antibacterial properties may offer alternative therapeutic agents against bacterial infections in aquaculture industry.
TL;DR: The results from different studies give hope for the possibility of graphene to be used in the regeneration of almost all tissues, including neural tissue implants or in the form of neural chips, which may allow in the future treatment of degenerative diseases and injuries of the central nervous system.
Abstract: In tissue engineering, the possibility of a comprehensive restoration of the tissue, structure or a portion of the organ is largely determined by the type of material used. A wide range of materials such as graphene and other carbon nanocompounds which have different physical and chemical properties can be expected to react differently upon contact with biomolecules, cells and tissues. This mini-review describes the current knowledge on biocompatibility of graphene and its derivatives with a variety of mammalian cells, such as osteoblasts, neuroendocrine cells, fibroblasts NIH/3T3 line, PMEFs (primary mouse embryonic fibroblasts), stem cells and neurons. The results from different studies give hope for the possibility of graphene to be used in the regeneration of almost all tissues, including neural tissue implants or in the form of neural chips, which may allow in the future treatment of degenerative diseases and injuries of the central nervous system.
TL;DR: Algino-oligosaccharides could be applied as a biological agent to control rice blast disease and the disease index caused by Magnaporthe grisea could be reduced from 17.74% to 10.81% and the protection efficacy was 39.06%.
Abstract: Rice blast caused by Magnaporthe grisea is considered to be one of the most devastating diseases in most rice-growing regions. In order to search for an effective agent to protect against rice infection, the elicitor activity of algino-oligosaccharides was evaluated in germinating rice, in which accumulation of oryzalexin C could be detected sensitively. The maximal elicitor activity was detected in germinating rice seedlings when the fractions of alginate degradation products with a degree of polymerization of 7.9 (S3) and 6.5 (S4) were used as elicitors. Algino-oligosaccharides could induce the enzyme activities of phenylalanine ammonia lyase, peroxidase and catalase in rice plant cells for protection of the plant against the invading pathogen. With utilization of algino-oligosaccharides, the disease index caused by Magnaporthe grisea could be reduced from 17.74% to 10.81% and the protection efficacy was 39.06%. These findings suggest that algino-oligosaccharides could be applied as a biological agent t...
TL;DR: Using 10-methacryloyloxy-decyl dihydrogenphosphate monomer-containing priming agents, e.g. Monobond Plus and Z-PRIME Plus, combined with sandblasting can be an effective method for resin bonding of zirconia restorations.
Abstract: The aim of this study was to evaluate the effects of sandblasting and different chemical bonding agents on shear bond strength of zirconia and conventional resin cement. In this study, 35 zirconia specimens were treated as follows: Group I: control; Group II: sandblasting; Group III: sandblasting + Monobond S; Group IV: sandblasting + Monobond Plus; Group V: sandblasting + Z-Prime Plus. The specimens in each group were bonded with conventional composite resin cement Variolink II. After cementation, specimens were stored in distilled water (at 37 °C) for 24 h and shear test was performed. The highest shear bond strength values were observed in Groups IV and V. The lowest shear bond strength values were observed in Group I. Using 10-methacryloyloxy-decyl dihydrogenphosphate monomer-containing priming agents, e.g. Monobond Plus and Z-PRIME Plus, combined with sandblasting can be an effective method for resin bonding of zirconia restorations.
TL;DR: The aim of this study was to reveal the role of Mn2+ in promoting the biosynthesis of surfactin by Bacillus subtilis ATCC 21332, which could arise more targeted suggestions on Surfactin yield promotion.
Abstract: Surfactin, one of the most effective biosurfactants, has great potential in commercial applications. Studies on effective methods to reduce surfactin's production cost are always a hotspot in the research field of biosurfactants. The aim of this study was to reveal the role of Mn2+ in promoting the biosynthesis of surfactin by Bacillus subtilis ATCC 21332, which could arise more targeted suggestions on surfactin yield promotion. In this study, B.subtilis was cultivated in media containing different Mn2+ concentrations. The obtained results showed that the yield of surfactin gradually increased upon Mn2+ addition (0.001 to 0.1 mmol/L) and achieved the maximal production of 1500 mg/L, which reached 6.2-fold of the yield obtained in media without Mn2+ addition. Correspondingly, the usage ratios of ammonium nitrate were improved. When the Mn2+ concentration was higher than 0.05 mmol/L, nitrate became the main nitrogen source, instead of ammonium, indicating that the nitrogen utilization pattern was also changed. An increase in nitrate reductase activity was observed and the increase upon Mn2+ dosage had a positive correlate with nitrate use, and then stimulated secondary metabolic activity and surfactin synthesis. On the other hand, Mn2+ enhanced the glutamate synthase activity, which increased nitrogen absorption and transformation and provided more free amino acids for surfactin synthesis.
TL;DR: In this paper, an alternative option for the production of geranyl propionate using nanobioconjugates consisting of Candida rugosa lipase adsorbed onto multi-walled carbon nanotubes (CRL-MWCNTs) was presented.
Abstract: Terpene esters of short-chain fatty acids are essential oils that have big importance in food, cosmetic and pharmaceutical industries as flavours and fragrances. Geraniol and citronellol are the most important substances. Considering the ever-increasing demand for such products, their enzymatic production from natural raw materials by using environmentally friendly and economically attractive processes may prove advantageous. In this contribution, we would like to present an alternative option for the production of geranyl propionate using nanobioconjugates consisting of Candida rugosa lipase adsorbed onto multi-walled carbon nanotubes (CRL-MWCNTs). We investigated the effects of incubation time, temperature, solvent log P and substrate molar ratio, and determined the optimum conditions. The yield of geranyl propionate catalysed by CRL-MWCNTs nanobioconjugates was significantly influenced by two factors, namely, temperature and time of the reaction. Under the optimum reaction conditions of 55 °C, solvent ...
TL;DR: In this article, a microbial biosurfactant produced by a Pseudomonas aeruginosa strain, identified as a lipopeptide by attenuated total reflectance Fourier transform infrared spectroscopy, was investigated for its efficacy in enhancing polycyclic aromatic hydrocarbons desorption and mobilization in a spiked soil system.
Abstract: There are often two phases in the desorption of polycyclic aromatic hydrocarbons (PAHs): an initial phase of rapid desorption and a subsequent phase of much slower release. By assessing the rapidly desorbing fraction of PAHs, a direct measure of the microbially degradable component of PAH contamination can be obtained and achievable bioremediation performances can be predicted. In this study, microbial biosurfactant produced by a Pseudomonas aeruginosa strain, identified as a lipopeptide by attenuated total reflectance Fourier transform infrared spectroscopy, was investigated for its efficacy in enhancing PAH desorption and mobilization in a spiked soil system. The desorption of pyrene and phenanthrene from the artificially spiked soil was enhanced 3.5–4.0 times at 700 mg L−1 lipopeptide amendment than at 150 mg L−1 amendment or in the unamended soil. The amount desorbed was generally in direct proportion to the amount of lipopeptide present. Mathematical modelling using a first-order two-compartment mode...
TL;DR: The good botanical identification of T. farfara and morphologically closer PA content species is a prerequisite for quality monitoring and control of plant based products.
Abstract: Tussilago farfara L. (Asteraceae) is widespread in Bulgaria and commonly known as ‘podbel.’ Although T. farfara is a common and widely used herb in folk medicine in the past and today, a study of a...
TL;DR: In this paper, a mixture of HNO3 and H2SO4 (1:3, v:v) was employed as the matrix for the adsorption of Candida rugosa lipase as nanobioconjugates (CRL-MWCNTs) for the production of methyl oleate.
Abstract: Esters, such as methyl oleate, are functionally important compounds in many industrial sectors, mainly as components for manufacturing of emulsifiers, detergents, intermediate stabilizers and wetting agents. Acid functionalization of multi-walled carbon nanotubes (F-MWCNTs) by using a mixture of HNO3 and H2SO4 (1:3, v:v) was employed as the matrix for the adsorption of Candida rugosa lipase (CRL) as nanobioconjugates (CRL-MWCNTs) for the production of methyl oleate. Structural information of the developed CRL-MWCNTs was confirmed using Fourier Transform Infrared spectroscopy, thermogravimetric analysis and transmission electron microscopy, which revealed a successful attachment of CRL onto the F-MWCNTs. Process parameters (reaction time, temperature and alcohol:acid molar ratio) were optimized for high percent conversion of methyl oleate. Structural analysis established that CRL was successfully attached to the surface of the F-MWCNTs. Under the optimized conditions, which were 13.87 h, 51 °C, molar ratio...
TL;DR: The essential oil characterized with stronger antifungal activity in comparison with pure cis- and trans-pinocamphone, α- andβ-pinene and β-phellandrene, and the essential oil inhibited both fluconazol-sensitive and fluconzol-resistant strains.
Abstract: The chemical composition of hyssop oil from Bulgaria was determined by gas chromatography with flame ionization detection and gas chromatography–mass spectrometry on two different chromatographic columns. The quantity of identified compounds was shown correspond to 97.2% and 98% of the total oil content. Among the detected compounds, cis-pinocamphone (48.98%–50.77%), β-pinene (13.38%–13.54%), trans-pinocamphone (5.78%–5.94%) and β-phellandrene (4.44%–5.17%) were the major compounds. Hyssop oil demonstrated antifungal activity against 52 clinical isolates and reference strains of Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis and Candida krusei. The essential oil characterized with stronger antifungal activity in comparison with pure cis- and trans-pinocamphone, α- and β-pinene and β-phellandrene. Essential oil of Hyssopus officinalis L. from Bulgaria inhibited both fluconazol-sensitive and fluconazol-resistant strains.
TL;DR: An efficient and rapid Agrobacterium-mediated tomato transformation protocol by using cotyledon and hypocotyl as explants is developed, and the received results are a base for a larger scale development of transformation procedure.
Abstract: We developed an efficient and rapid Agrobacterium-mediated tomato transformation protocol by using cotyledon and hypocotyl as explants. The transgenic nature of the regenerants was confirmed through β-glucuronidase activity staining, polymerase chain reaction (PCR), quantitative real-time PCR (qPCR) analysis and northern blot analysis. In the used protocol, the optimized experimental conditions of the tomato genetic transformation were Agrobacterium liquid concentration, equivalent to optical density (OD600) of 1.0, 20 min (cotyledon) or 30 min (hypocotyl) infection time and 2 d of co-culturing period. The optimized medium for shoot induction was Murashige & Skoog (MS) medium + 0.5 mg/L indole-3-acetic acid (IAA) + 0.5 mg/L 6-benzylaminopurine (BAP) for cotyledon and MS + 0.5 mg/L IAA + 2.0 mg/L BAP for hypocotyl. The root induction rate was the highest on the MS medium, supplemented with 0.1 mg/L IAA. The transformation frequency reached 40% per explant. The received results are a base for a larger scale...
TL;DR: In this article, the authors discuss the problem of waste materials in the control industrialization process since nineteenth century and the trend towards consumer society have resulted in an enormous amount of waste material.
Abstract: Uncontrolled industrialization process since nineteenth century and the trend towards consumer society have resulted in an enormous amount of waste materials. As a result of this problem, managemen...
TL;DR: Chlorophyll a and b, carotenoids, net photosynthetic rate and antioxidative enzymes, viz., superoxide dismutase and catalase activities were measured in leaf tissues during ex vitro acclimatization at 0, 7, 14, 21 and 28 days and suggested the adjustment of the in vitro propagated plantlets to ex vitro conditions.
Abstract: An efficient system for in vitro propagation of the endangered medicinal plant Rauvolfia serpentina has been developed. Proliferation of shoots was achieved from nodal segment explants, excised fro...