An efficient callus-based in vitro regeneration protocol for Warburgia Ugandensis Sprague,an important medicinal plant in Africa

Warburgia ugandensis Sprague is a woody species in the family Canellaceae and an important source of medicines in Africa. Natural propagation of W. ugandensis is problematic due to its recalcitrant seeds and lack of an efficient in vitro regeneration system for this species. This study describes an efficient regeneration protocol. Petiole bases and shoot tips were used as explants. Callus tissue developed when the explants were cultured on Murashige and Skoog medium containing 30 g L⁻¹ sucrose and 7 g L⁻¹ agar (MS30 medium), supplemented with 1.0 mg L⁻¹ indole-3-butyric acid (IBA), 1.6 mg L⁻¹ 6-benzylaminopurine (BA), and 0.1 mg L⁻¹ thidiazuron (TDZ). Adventitious buds were efficiently induced from the callus when the MS30 medium was supplemented with 0.8 mg L⁻¹ BA and 0.2 mg L⁻¹ IBA. Root induction occurred within 7–10 d on half-strength MS30 medium supplemented with 0.8–1.0 mg L⁻¹ 1-napthalene acetic acid (NAA), 0.2 mg L⁻¹ IBA, and 0.03% (w/v) activated charcoal (AC). Roots were followed by root elongation on the same medium but lacking NAA and IBA. Approximately 50% of the plantlets cultured produced roots, while more than 80% of the plantlets survived and successfully grew to maturity.

     

A chiral,porous, organic cage‐based,enantioselective potentiometric sensor for 2‐aminobutanol

A new enantioselective potentiometric sensor containing R‐type chiral porous organic cage CC9 as the chiral selector was designed for the assay of 2‐aminobutanol. Optimized membrane electrodes displayed a linear dynamic range from 10⁻³ ~ 10⁻¹ mol·L⁻¹ with a detection limit of 2.5 × 10⁻⁴ mol·L⁻¹ and a Nernstian response of 27 ± 0.5mV·decade⁻¹ toward S‐2‐aminobutanol within the pH range 7.0–10.0. The potentiometric enantioselectivity coefficient ( ) of this sensor was −1.333, indicating that the porous organic cage‐based electrode exhibited good discrimination toward S‐2‐aminobutanol over R‐2‐aminobutanol.     

Effective biodegradation of 2,4,6-trinitrotoluene using a novel bacterial strain isolated from TNT-contaminated soil

In this environmental-sample based study, rapid microbial-mediated degradation of 2,4,6-trinitrotoluene (TNT) contaminated soils is demonstrated by a novel strain, Achromobacter spanius STE 11. Complete removal of 100 mg L⁻¹ TNT is achieved within only 20 h under aerobic conditions by the isolate. In this bio-conversion process, TNT is transformed to 2,4-dinitrotoluene (7 mg L⁻¹), 2,6-dinitrotoluene (3 mg L⁻¹), 4-aminodinitrotoluene (49 mg L⁻¹) and 2-aminodinitrotoluene (16 mg L⁻¹) as the key metabolites. A. spanius STE 11 has the ability to denitrate TNT in aerobic conditions as suggested by the dinitrotoluene and NO₃ productions during the growth period. Elemental analysis results indicate that 24.77 mg L⁻¹ nitrogen from TNT was accumulated in the cell biomass, showing that STE 11 can use TNT as its sole nitrogen source. TNT degradation was observed between pH 4.0–8.0 and 4–43 °C; however, the most efficient degradation was at pH 6.0–7.0 and 30 °C.     

Effects of heavy metals on aerobic denitrification by strain Pseudomonas stutzeri PCN-1

Effects of heavy metals on aerobic denitrification have been poorly understood compared with their impacts on anaerobic denitrification. This paper presented effects of four heavy metals (Cd(II), Cu(II), Ni(II), and Zn(II)) on aerobic denitrification by a novel aerobic denitrifying strain Pseudomonas stutzeri PCN-1. Results indicated that aerobic denitrifying activity decreased with increasing heavy metal concentrations due to their corresponding inhibition on the denitrifying gene expression characterized by a time lapse between the expression of the nosZ gene and that of the cnorB gene by PCN-1, which led to lower nitrate removal rate (1.67∼6.67 mg L⁻¹ h⁻¹), higher nitrite accumulation (47.3∼99.8 mg L⁻¹), and higher N₂O emission ratios (5∼283 mg L⁻¹/mg L⁻¹). Specially, promotion of the nosZ gene expression by increasing Cu(II) concentrations (0∼0.05 mg L⁻¹) was found, and the absence of Cu resulted in massive N₂O emission due to poor synthesis of N₂O reductase. The inhibition effect for both aerobic denitrifying activity and denitrifying gene expression was as follows from strongest to least: Cd(II) (0.5∼2.5 mg L⁻¹) > Cu(II) (0.5∼5 mg L⁻¹) > Ni(II) (2∼10 mg L⁻¹) > Zn(II) (25∼50 mg L⁻¹). Furthermore, sensitivity of denitrifying gene to heavy metals was similar in order of nosZ > nirS ≈ cnorB > napA. This study is of significance in understanding the potential application of aerobic denitrifying bacteria in practical wastewater treatment.

     

Genetic homogeneity and high shoot proliferation in banana (Musa acuminata Colla) by altering medium thiamine level and sugar type

To enhance the multiplication rate in Musa acuminata Colla (banana; ‘Grand Nain’) organogenesis, higher amounts of thiamine along with different sugar types and concentrations were evaluated at the proliferation phase. Thiamine at 1, 10, 50, 100, and 200 mg L⁻¹ was compared with 0.1 mg L⁻¹ thiamine found in conventional Murashige and Skoog (MS) medium. Maximum proliferation of banana was induced with 100 mg L⁻¹ thiamine. Additionally, 15, 30, and 45 g L⁻¹ sucrose, glucose, fructose, and sorbitol combined with regular and optimal levels of thiamine were tested. Glucose at 30 g L⁻¹ most improved shoot proliferation alone and enhanced shoot proliferation further, when combined with 100 mg L⁻¹ thiamine, followed by sucrose and fructose, whereas sorbitol completely inhibited growth and caused tissue browning. All evaluated vegetative traits were significantly affected by sugar type and concentration, and thiamine levels, unlike the photosynthetic pigments. Moreover, genetic stability of the plants recovered from the enhanced protocol was confirmed by inter-simple sequence repeats (ISSR) and randomly amplified polymorphic DNA (RAPD) analysis. A total of 230 bands generated by both marker types were monomorphic for the randomly selected regenerated plants, compared with their mother plant. Thus, the proliferation medium supplemented with 30 g L⁻¹ glucose and 100 mg L⁻¹ thiamine could be recommended for banana organogenesis. Results herein are of great importance and helpful in enhancing the commercial in vitro propagation protocols of banana, without the need of increasing the number of subcultures, which can cause somaclonal variation.

     

Synthesis and characterization of ion‐imprinted resin for selective removal of UO2(II) ions from aqueous medium

In this work, uranyl ion‐imprinted resin based on 2‐(((4‐hydroxyphenyl)amino)methyl)phenol was synthesized by condensation polymerization of its uranyl complex in presence of resorcinol and formaldehyde cross‐linkers. Numerous instrumental techniques including elemental analysis, Fourier transform infrared spectroscopy, ultraviolet, ¹H along with ¹³C nuclear magnetic resonance spectroscopy have been employed for complete characterization of the synthesized ligand and its uranyl complex. Additionally, the obtained ion‐imprinted and non‐imprinted resins were investigated using scanning electron microscope and Fourier transform infrared spectroscopy. The effects of various essential parameters such as pH, temperature and contact time on removal of uranyl ions have been examined, and the results indicated that the obtained resin exhibited the optimum activity at pH 5. Furthermore, the adsorption process was spontaneous at all studied temperatures and followed the second‐order kinetics model. Also, Langmuir adsorption isotherm exhibited the best fit with the experimental results with maximum adsorption capacity 139.3 mg/g. Moreover, the selectivity studies revealed that the ion‐imprinted resin exhibited an obvious affinity toward the uranyl ions in presence of other metal ions compared with the non‐imprinted resin. Copyright © 2015 John Wiley & Sons, Ltd.     

Use of bioreactors for large-scale multiplication of sugarcane (Saccharum spp.), energy cane (Saccharum spp.), and related species

The objective of this study was to set up a plant micropropagation facility to mass propagate sugarcane, energy cane, and related clonally propagated species. An efficient methodology for micropropagation of energy cane and perennial grasses using temporary immersion bioreactors was developed. Several different methods of tissue culture initiation, multiplication, and rooting were evaluated for several varieties of sugarcane (Saccharum officinarum L.) and sugarcane-related species such as Erianthus spp., Miscanthus spp., and Sorghum spp. × sugarcane hybrids, all from a germplasm collection. Apical meristem cultures were initiated for all genotypes that were micropropagated, when liquid or semisolid Murashige and Skoog (MS) medium was used, which was supplemented with 0.1–0.2 mg L⁻¹ BAP, 0.1 mg L⁻¹ kinetin, 0–0.1 mg L⁻¹ NAA, and 0–0.2 μg L⁻¹ giberellic acid. These cultures produced shoots between 4 and 8 wk after initiation. Shoot regeneration from leaf rolls or immature inflorescences was observed as early as 4 wk after initiation. Shoot multiplication was successful for all genotypes cultured in MS medium with 0.2 mg L⁻¹ BAP and 0.1 mg L⁻¹ kinetin. Energy cane had a significantly higher combined multiplication rate when grown under four or five LED lamps than when grown under three LED lamps, or under fluorescent lights in a growth chamber. The addition of 2 mg L⁻¹ NAA produced faster and better rooting in all of the genotypes tested. Shoots produced well-developed roots after one cycle of 15–21 d in the bioreactors. The maximum number of plantlets produced per bioreactor was 1080. Plantlets developed a vigorous root system and were ready to be transplanted into the field after 2 mo. A protocol was standardized for different energy cane clones that were recommended for their biomass production and cell wall composition. Different tissues were used to speed up or facilitate tissue culture initiation. Visual assessment of micropropagated plants in the field did not show any off-types, based on gross morphological changes of plant morphology or disease reaction, compared to plants of the same genotype derived from a traditional propagation method (stem cuttings). This is the first report of energy cane and Miscanthus spp. micropropagation using the SETIS bioreactor.

     

Competition of As and other Group 15 elements for surface binding sites of an extremophilic Acidomyces acidophilus isolated from a historical tin mining site

An arsenic-resistant fungal strain, designated WKC-1, was isolated from a waste roaster pile in a historical tin mine in Cornwall, UK and successfully identified to be Acidomyces acidophilus using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF MS) proteomic-based biotyping approach. WKC-1 showed considerable resistance to As⁵⁺ and Sb⁵⁺ where the minimal inhibitory concentration (MIC) were 22500 and 100 mg L⁻¹, respectively, on Czapex-Dox Agar (CDA) medium; it was substantially more resistant to As⁵⁺ than the reference strains CBS 335.97 and CCF 4251. In a modified CDA medium containing 0.02 mg L⁻¹ phosphate, WKC-1 was able to remove 70.30% of As⁵⁺ (100 mg L⁻¹). Sorption experiment showed that the maximum capacity of As⁵⁺ uptake was 170.82 mg g⁻¹ dry biomass as predicted by the Langmuir model. The presence of Sb⁵⁺ reduced the As⁵⁺ uptake by nearly 40%. Based on the Fourier-transform infrared spectroscopy (FT-IR) analysis, we propose that Sb is competing with As for these sorption sites: OH, NH, CH, SO₃ and PO₄ on the fungal cell surface. To our knowledge, this is the first report on the impact of other Group 15 elements on the biosorption of As⁵⁺ in Acidomyces acidophilus.

     

Effect of molybdenum on secondary metabolic process of glycyrrhizic acid in Glycyrrhiza uralensis Fisch.

A pot experiment was conducted to investigate into effects of molybdenum (Mo) on the secondary metabolic process of glycyrrhizic acid (GA). One-year-old seedlings were grown in pots with washed vermiculite and sand. Hoagland nutrition solution was irrigated with four concentrations: 0, 0.52, 5.2 and 10.4 mg L⁻¹. The accumulations of GA and its biosynthetic precursors (β-amyrin and squalene) and then expression of the key synthase (β-amyrin synthase, β-AS) were studied on 35, 70 and 105 d. In the early stage, that was on the 35 and 70 d, the contents of squalene and GA, and the expression of β-AS gene under 0.52 and 5.2 mg L⁻¹ Mo treatments were significantly higher than that under 0 and 10.4 mg L⁻¹ Mo. There was a contrary result of β-amyrin. However, the content of squalene under 0 mg L⁻¹ Mo was the highest on 105 d. Thus, it suggested an appropriate concentration of Mo could promote the accumulation of GA, by affecting the biosynthetic process of GA at a certain time. Practically, the time and amount of application of Mo on Glycyrrhiza uralensis should be the noted.     

Mycoremediation of oil contaminant by Pleurotus florida (P.Kumm) in liquid culture

This study investigated the potential functions of Pleurotus florida (an edible mushroom) in the biodegradation of gas oil at concentrations of 0 (control), 2.5, 5, and 10% (V: V) for 30 days. The gas oil increased dry weight and protein concentration in all treatments (by an average of 19.5 and 108%, respectively). Moreover, the pH, surface tension (ST), and interfacial tension (IFT) were reduced by the mushroom supplementation. The lowest surface tension (31.9 mN m⁻¹) and the highest biosurfactant production belonged to the 10% gas oil treatment (0.845 ± 0.03 mg mL⁻¹). The results demonstrated that the adsorption isotherm agreed well with the Langmuir isotherm. The maximum Langmuir adsorption capacity was calculated at 0.743 mg g⁻¹ wet biomass of P. florida. The fungal supplementation efficiently remedied the total petroleum hydrocarbons (TPHs) by an average of 55% after 30 days. Gas chromatography (GC) analysis revealed that P. florida effectively detoxified C₁₃–C₂₈ hydrocarbons, Pristane, and Phytane, implying its high mycoremediation function. The toxicity test showed that mycoremediation increased the germination by an average of 35.82% ± 8.89 after 30 days. Laccase activity increased significantly with increasing gas oil concentration in the treatments. The maximum laccase activity was obtained in the 10% gas oil treatment (142.25 ± 0.72 U L⁻¹). The presence of pollutants was also associated with induction in the tyrosinase activity when compared to the control. These results underline the high mycoremediation capacity of P. florida through the involvement of biosurfactants, laccase, and tyrosinase.     

Highly efficient regeneration and medicinal component determination of Phellodendron chinense Schneid

Phellodendron chinense Schneid is an important Chinese herb with berberine and phellodendrine in stems and leaves, but with little information available on in vitro culture of this species. Disinfection of explants in 75% alcohol for 45 s, sterilization in 0.1% HgCl₂ for 20 min, and submersion in 1.0 mol L⁻¹ gibberellin3 (GA₃) solution for 24 h was the optimal condition for seed germination. Murashige and Skoog’s (MS) medium supplemented with 2.0 mg L⁻¹ 6-benzylaminopurine (6-BA) in combination with 1.5 mg L⁻¹ 1-naphthylacetic acid (NAA) was optimal for callus induction. MS medium supplemented with 2.0 mg L⁻¹ 6-BA was the appropriate medium for induction of adventitious shoots, and 1/2MS medium supplemented with 2.0 mg L⁻¹ indole-3-butytric acid (IBA) and 0.5% active carbon was the optimal medium for root induction. The 15-d survival rate of regenerated plantlets after transplanting to basins containing perlite and peat moss (1:4) was greater than 80%, and the berberine and phellodendrine accumulation was lower in callus compared with regenerated plantlets. The establishment of highly efficient regeneration system provides technical support for genetic breeding of Phellodendron chinense Schneid.

     

Modification of light intensity influence essential oils content,composition and antioxidant activity of thyme,marjoram and oregano

Thymus vulgaris L. (thyme), Origanum majorana L. (marjoram), and Origanum vulgare L. (oregano) were used to determine whether light modification (plants grown under nets with 40% shaded index or in un-shaded open field) could improve the quantity and quality of essential oils (EOs) and antioxidant activity. The yield of EOs of thyme, marjoram, and oregano obtained after 120 min of hydrodistillation was 2.32, 1.51, and 0.27 mL/100 g of plant material, respectively. At the same time under shading conditions plants synthetized more EOs (2.57, 1.68, and 0.32 mL/100 g of plant material). GC/MS and GC/FID analyses were applied for essential oils determinations. The main components of the thyme essential oil are thymol (8.05–9.35%); γ-terpinene (3.49–4.04%); p-cymene (2.80–3.60%) and caryophyllene oxide (1.54–2.15%). Marjoram main components were terpinene 4-ol (7.44–7.63%), γ-terpinene (2.82–2.86%) and linalool (2.04–2.65%) while oregano essential oil consisted of the following components: caryophyllene oxide (3.1–1.93%); germacrene D (1.17–2.0%) and (E)-caryophyllene (1.48–1.1%). The essential oil from thyme grown under shading (EC₅₀ value after 20 min of incubation) have shown the highest antioxidant activity – 0.85 mg mL⁻¹ in comparison to marjoram and oregano (shaded plants EC₅₀ 19.97 mg mL⁻¹ and 7.02 mg mL⁻¹ and unshaded, control plants EC₅₀ 54.01 mg mL⁻¹ and 7.45 mg mL⁻¹, respectively). The medicinal plants are a good source of natural antioxidants with potential application in the food and pharmaceutical industries. For production practice, it can be recommended to grow medicinal plants in shading conditions to achieve optimal quality parameters.     

Designing chitosan based magnetic beads with conocarpus waste-derived biochar for efficient sulfathiazole removal from contaminated water

The development of a simple method to synthesize highly efficient and stable magnetic microsphere beads for sulfathiazole (STZ) removal from contaminated aqueous media was demonstrated in this study. Conocarpus (Conocarpus erectus L.) tree waste (CW) derived biochar (BC) was modified to fabricate chitosan-BC (CBC) and magnetic CBC (CBC-Fe) microsphere beads. Proximate, chemical, and structural properties of the produced adsorbents were investigated. Kinetics, equilibrium, and pH adsorption batch trials were conducted to evaluate the effectiveness of the synthesized adsorbents for STZ removal. All adsorbents exhibited the highest STZ adsorption at pH 5.0. STZ adsorption kinetics data was best emulated using pseudo-second order and Elovich models. The equilibrium adsorption data was best emulated using Langmuir, Freundlich, Redlich–Peterson, and Temkin models. CBC-Fe demonstrated the highest Elovich, pseudo-second order, and power function rate constants, as well as the highest apparent diffusion rate constant. Additionally, Langmuir isotherm predicted maximum adsorption capacity was the highest for CBC-Fe (98.67 mg g⁻¹), followed by CBC (56.54 mg g⁻¹) and BC (48.63 mg g⁻¹). CBC-Fe and CBC removed 74.5%–108.8% and 16.2%–25.6% more STZ, respectively, than that of pristine BC. π-π electron-donor–acceptor interactions and Lewis acid-base reactions were the main mechanisms for STZ removal; however, intraparticle diffusion and H-bonding further contributed in the adsorption process. The higher efficiency of CBC-Fe for STZ adsorption could be due to its magnetic properties as well as stronger and conducting microsphere beads, which degraded the STZ molecules through generation of HO^• radicals.     

Temperature and hypoxia on oxidative stress responses in pacu Piaractus mesopotamicus

The aim of this study was to verify the effects of the interaction between different temperatures and levels of dissolved oxygen in the oxidative stress parameters of pacu juveniles. A total of 81 pacu juveniles (61.7 ± 9.1 g) were exposed to three temperatures (18, 23, and 28 °C), acclimated for a period of 30 days, and then submitted to three levels of dissolved oxygen: control or normoxia (7 mg L⁻¹); moderate hypoxia (4 mg L⁻¹); and severe hypoxia (2 mg L⁻¹) for 12 h. Glutathione-S-transferase (GST) activity, total antioxidant capacity against peroxyl radicals (ACAP), and protein thiol content (PSH) and LPO (lipid peroxidation) [measured by the TBARS] were measured in gill, liver, muscle and brain. The results indicated that the interaction between different temperatures and dissolved oxygen levels caused alterations in the antioxidant system and induced lipid and protein damage in pacu juveniles. In addition, the effects were organ specific. In conclusion, exposure to moderate and severe hypoxia affect oxidative stress parameters and have been shown to be organ-specific in pacu juveniles. The interaction between 23 °C and hypoxia caused greater disturbances in oxidative stress markers, such as PSH in the gills and liver and LPO in the muscle.     

Estuarine sediment hydrocarbon-degrading microbial communities demonstrate resilience to nanosilver

Little is currently known about the potential impact of silver nanoparticles (AgNPs) on estuarine microbial communities. The Colne estuary, UK, is susceptible to oil pollution through boat traffic, and there is the potential for AgNP exposure via effluent discharged from a sewage treatment works located in close proximity. This study examined the effects of uncapped AgNPs (uAgNPs), capped AgNPs (cAgNPs) and dissolved Ag₂SO₄, on hydrocarbon-degrading microbial communities in estuarine sediments. The uAgNPs, cAgNPs and Ag₂SO₄ (up to 50 mg L⁻¹) had no significant impact on hydrocarbon biodegradation (80–92% hydrocarbons were biodegraded by day 7 in all samples). Although total and active cell counts in oil-amended sediments were unaffected by silver exposure; total cell counts in non-oiled sediments decreased from 1.66 to 0.84 × 10⁷ g⁻¹ dry weight sediment (dws) with 50 mg L⁻¹ cAgNPs and from 1.66 to 0.66 × 10⁷ g⁻¹ dws with 0.5 mg L⁻¹ Ag₂SO₄ by day 14. All silver-exposed sediments also underwent significant shifts in bacterial community structure, and one DGGE band corresponding to a member of Bacteroidetes was more prominent in non-oiled microcosms exposed to 50 mg L⁻¹ Ag₂SO₄ compared to non-silver controls. In conclusion, AgNPs do not appear to affect microbial hydrocarbon-degradation but do impact on bacterial community diversity, which may have potential implications for other important microbial-mediated processes in estuaries.     

Somatic embryogenesis to overcome low seed viability and conserve wild banana (Ensete superbum (Roxb.) Cheesman)

The seed viability, ex vitro germination, and percentage of in vitro zygotic embryo germination were found to be very low in Ensete superbum (Roxb.) Cheesman. Only 33.33% of seeds were viable, and the ex vitro germination percentage was only 5%, while the percentage of in vitro zygotic embryo germination was 33%. Somatic embryogenesis experiments produced competent callus on Murashige and Skoog (MS) medium supplemented with 2.5 mg L⁻¹ 2,4-D and 3 mg L⁻¹ BAP from inflorescence explants. The embryogenic callus produced the maximum number of somatic embryos on MS basal medium kept in a dark chamber for 15 wk. Half-strength MS medium supplemented with 500 mg L⁻¹ glutamine was optimal for somatic embryo germination and development of plantlets. Regenerated plants had 80 to 90% survival rate. Therefore, somatic embryogenesis can be considered as an efficient method to overcome a drastic reduction in population and to achieve germplasm conservation.

     

Surface Chirality of Gly‐Pro Dipeptide Adsorbed on a Cu(110) Surface

The adsorption of chiral Gly‐Pro dipeptide on Cu(110) has been characterized by combining in situ polarization modulation infrared reflection absorption spectroscopy (PM‐RAIRS) and X‐ray photoelectron spectroscopy (XPS). The chemical state of the dipeptide, and its anchoring points and adsorption geometry, were determined at various coverage values. Gly‐Pro molecules are present on Cu(110) in their anionic form (NH₂/COO⁻) and adsorb under a 3‐point binding via both oxygen atoms of the carboxylate group and via the nitrogen atom of the amine group. Low‐energy electron diffraction (LEED) and scanning tunneling microscopy (STM) have shown the presence of an extended 2D chiral array, sustained via intermolecular H‐bonds interactions. Furthermore, due to the particular shape of the molecule, only one homochiral domain is formed, creating thus a truly chiral surface. Chirality 27:411–416, 2015. © 2015 Wiley Periodicals, Inc.     

Sulfanilic acid‐modified chitosan mini‐spheres and their application for lysozyme purification from egg white

A cation exchange matrix with zwitterionic and multimodal properties was synthesized by a simple reaction sequence coupling sulfanilic acid to a chitosan based support. The novel chromatographic matrix was physico‐chemically characterized by ss‐NMR and ζ potential, and its chromatographic performance was evaluated for lysozyme purification from diluted egg white. The maximum adsorption capacity, calculated according to Langmuir adsorption isotherm, was 50.07 ± 1.47 mg g^?1 while the dissociation constant was 0.074 ± 0.012 mg mL^?1. The process for lysozyme purification from egg white was optimized, with 81.9% yield and a purity degree of 86.5%, according to RP‐HPLC analysis. This work shows novel possible applications of chitosan based materials. The simple synthesis reactions combined with the simple mode of use of the chitosan matrix represents a novel method to purify proteins from raw starting materials. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:387–396, 2018     

Biodegradation of phenol using hairy roots of Helianthus annuus L.

Phenol is a common pollutant which is found in wastewater of many industries and removal of phenol from the industrial effluents is a major challenge. Recently, the use of hairy roots has been probed for the removal of phenol. In the present study, phenol at various concentrations (100–500 mg L⁻¹) was treated with hairy roots of Helianthus annuus (sunflower hairy roots, SHRs). SHRs removed 100 mg L⁻¹ of phenol after 144 h of incubation. The effect of polyethylene glycol (PEG), l-proline and d-glucose on the rate of phenol removal was also studied. l-proline enhanced the removal efficiency of SHRs resulting in the removal of 100 mg L⁻¹ of phenol after 24 h while PEG did not show any effect on removal. Peroxidase activity was induced after 24 h of phenol addition. Phenol metabolism to generate catechol as a major metabolite was confirmed using HPLC and GC–MS analyses. The detection of small amounts of cis-cis muconic acid and fumaric acid in the reaction medium suggests that these metabolites are produced from the ring cleavage of catechol. The phytotoxicity and cytotoxicity results suggest the non-toxic nature of the resulting phenol metabolites.     

Acclimation of arsenic-resistant Fe(II)-oxidizing bacteria in aqueous environment

This study investigated the potential of the Fe(II)-oxidizing bacteria in removing arsenic in aqueous environment. The bacteria were isolated from the batch of tap water and rusty iron wires, and were acclimated to culture media amended with arsenic concentrations, gradually increasing from 100 μg L⁻¹ to 100 mg L⁻¹. Acclimated bacteria with enhanced arsenic tolerance were used to remove arsenic from the aqueous solution. These bacteria belonged to Pseudomonas species according to 16S rRNA gene sequences. Extracellular enzymes produced by these bacteria played important roles in microbial Fe(II) oxidization and Fe oxide precipitation. Moreover, these bacteria survived and propagated in high arsenic condition (100 mg L⁻¹ As). However, after As(III/V) acclimation, morphological characteristics of the bacteria showed some changes, e.g., shrinking of long bacillus. XRD (X-ray diffraction) patterns indicated that Fe oxide precipitations by Fe(II)-oxidizing bacteria in Fe-rich culture medium were poorly-crystallized ferrihydrites. Adsorption on the biogenic ferrihydrites greatly contributed to high arsenic removal efficiency of Fe(II)-oxidizing bacteria.