Micronucleus assay in bovine lymphocytes after exposure to bisphenol A in vitro

Bisphenol A (BPA) [2,2-bis-(4-hydroxyphenyl) propane] is an important industrial agent, made by combining acetone and phenol, that is used extensively as a monomer in the production of polycarbonate plastics and as a precursor of epoxy resins. Micronucleus assays have served as an index of cytogenetic damage in in vivo and in vitro studies. We studied the genotoxic and cytotoxic effects of BPA on bovine peripheral lymphocytes in vitro. Lymphocyte cultures from two donors were exposed to four different concentrations of BPA (1?×?10^?4, 1?×?10^?5, 1?×?10^?6, and 1?×?10^?7 mol.L^?1) for 48 h. The highest concentration of BPA (1?×?10^?4 mol.L^?1) resulted in a significant increase in the number of micronuclei in comparison with the negative control (67.50?±?2.121/1,000 binucleated cells versus 36.0?±?5.657/1,000 binucleated cells in the DMSO control, P??=??0.018). BPA did not affect the nuclear division index at any treatment concentrations. The present results thus demonstrate a significant genotoxic effect by BPA on bovine peripheral lymphocytes in vitro, only at the highest concentration.     

Phytoremediation of Bisphenol A and Total Dissolved Solids by the Mangrove Plant,Bruguiera Gymnorhiza

Bruguiera gymnorhiza, an evergreen mangrove tree, is tolerant of bisphenol A (BPA) and has potential BPA removal capability. BPA is highly toxic to plants at high concentrations, wherein they exhibit damaged symptoms such as chlorosis, necrosis, and wilting. The LD₅₀ of BPA toxicity for this plant was statistically estimated to be 39.97 mg L^–1. B. gymnorhiza can reduce COD from 15408 ± 246 to 49 ± 30 mg L^–1 by (approximately 99% reduction of the initial value) and can reduce content to levels below the industrial effluent standard of Thailand (<120 mg L^–1) within 48 days. This plant can completely remove BPA from the solution within 51 days of treatment. Polysaccharides and organic acids were found in the solution and were caused by plant response to the toxicity of BPA. In addition, B. gymnorrhiza can also reduce total dissolved solids (TDS) and salinity in real wastewater. Therefore, B. gymnorrhiza has potential for removal of BPA and TDS in contaminated in wastewater.     

Effect of trace elements and optimization of their composition for the nitrification of a heterotrophic nitrifying bacterium, <Emphasis Type="Italic">Acinetobacter harbinensis</Emphasis> HITLi7<Superscript>T</Superscript>, at low temperature

The effects of trace elements on ammonium degradation performance and extracellular polymeric substances (EPS) secretion of Acinetobacter harbinensis HITLi7^T at low temperature were investigated. Response surface methodology (RSM) was applied to obtain the optimal composition of trace elements and analyze their correlation. In this study, the results indicated that the ammonium removal performance could be enhanced by the presence of 0.1 mg L^?1 Fe, Mn, or B in pure cultivation. When the concentrations of Fe and Mn were 0.2 mg L^?1, the ammonium removal rates of the novel strain HITLi7^T were 0.49 ± 0.01 mg L^?1·h^?1 and 0.58 ± 0.01 mg L^?1·h^?1, respectively, while it was the low concentration of 0.05 mg L^?1 B that showed the maximum ammonium removal rate (0.56 ± 0.02 mg L^?1·h^?1) of strain HITLi7^T. The regression model was obtained and the optimal formulation of trace elements was: B 0.064 mg L^?1, Fe 0.12 mg L^?1, and Mn 0.1 mg L^?1. Based on these values, the experimental ammonium removal rate could reach 0.59 mg L^?1·h^?1, which matched well with the predicted response. The study also found that the addition of trace elements, causing high ammonium removal rates, resulted in a high polysaccharide (PS) ratio in the EPS secreted by Acinetobacter harbinensis HITLi7^T. Especially under the optimal conditions, the PS ratio reached the highest value of 49.9%.     

Alleviation of metal and BTEX inhibition on BTEX degradation using PVA-immobilized degrader: kinetic model of BTEX degradation

Alleviation of metal inhibition on BTEX degradation using PVA-immobilized degrader (Mycobacterium sp. CHXY119) was investigated. When BTEX of 29 mg L^?1 [B:T:E:X = 1:1:1:1 (mg)] was used, more than 99 % of BTEX was simultaneously degraded by the free cells within 170 h. In contrast, BTEX of 114–172 mg L^?1 seriously inhibited degradation. High concentrations of metals (Mn²⁺: 15, Ni²⁺: 10, and Zn²⁺: 10 mg L^?1) also strongly inhibited BTEX degradation by the free cells at BTEX of 29 mg L^?1. Immobilization of degraders alleviated the inhibition of BTEX and heavy metals at high concentrations. A modified non-competitive inhibition model well described the BTEX degradation by the free and immobilized cells in the absence and presence of metal ions (R ² = 0.92–0.99). The above results provide valuable information on treatment of metal-BTEX co-contaminated wastewater by the immobilized degrader.     

Enhancing ethanol production from cellulosic sugars using <Emphasis Type="Italic">Scheffersomyces (Pichia) stipitis</Emphasis>

Studies were performed on the effect of CaCO₃ and CaCl₂ supplementation to fermentation medium for ethanol production from xylose, glucose, or their mixtures using Scheffersomyces (Pichia) stipitis. Both of these chemicals were found to improve maximum ethanol concentration and ethanol productivity. Use of xylose alone resulted in the production of 20.68 ± 0.44 g L^?1 ethanol with a productivity of 0.17 ± 0.00 g L^?1 h^?1, while xylose plus 3 g L^?1 CaCO₃ resulted in the production of 24.68 ± 0.75 g L^?1 ethanol with a productivity of 0.21 ± 0.01 g L^?1 h^?1. Use of xylose plus glucose in combination with 3 g L^?1 CaCO₃ resulted in the production of 47.37 ± 0.55 g L^?1 ethanol (aerobic culture), thus resulting in an ethanol productivity of 0.39 ± 0.00 g L^?1 h^?1. These values are 229 % of that achieved in xylose medium. Supplementation of xylose and glucose medium with 0.40 g L^?1 CaCl₂ resulted in the production of 44.84 ± 0.28 g L^?1 ethanol with a productivity of 0.37 ± 0.02 g L^?1 h^?1. Use of glucose plus 3 g L^?1 CaCO₃ resulted in the production of 57.39 ± 1.41 g L^?1 ethanol under micro-aerophilic conditions. These results indicate that supplementation of cellulosic sugars in the fermentation medium with CaCO₃ and CaCl₂ would improve economics of ethanol production from agricultural residues.     

Butanol production from concentrated lactose/whey permeate: Use of pervaporation membrane to recover and concentrate product

In these studies, butanol (acetone butanol ethanol or ABE) was produced from concentrated lactose/whey permeate containing 211 g L^?1 lactose. Fermentation of such a highly concentrated lactose solution was possible due to simultaneous product removal using a pervaporation membrane. In this system, a productivity of 0.43 g L^?1 h^?1 was obtained which is 307 % of that achieved in a non-product removal batch reactor (0.14 g L^?1 h^?1) where approximately 60 g L^?1 whey permeate lactose was fermented. The productivity obtained in this system is much higher than that achieved in other product removal systems (perstraction 0.21 g L^?1 h^?1 and gas stripping 0.32 g L^?1 h^?1). This membrane was also used to concentrate butanol from approximately 2.50 g L^?1 in the reactor to 755 g L^?1. Using this membrane, ABE selectivities and fluxes of 24.4–44.3 and 0.57–4.05 g m^?2 h^?1 were obtained, respectively. Pervaporation restricts removal of water from the reaction mixture thus requiring significantly less energy for product recovery when compared to gas stripping.     

Growth Kinetics of Microbacterium lacticum and Nitrate-Dependent Degradation of Ethylbenzene under Anaerobic Conditions

A pure strain of Microbacterium lacticum DJ-1 capable of anaer-obic biodegradation of ethylbenzene was isolated from soil contaminated with gasoline. Growth of the strain and biodegradation of ethylbenzene in batch cultures led to stoichiometric reduction of nitrate. M. lacticum DJ-1 could degrade 100 mg L^?1 of ethylbenzene completely, with a maximum degradation rate of 15.02 ± 1.14 mg L^?1 day^?1. Increasing the initial concentration of ethy-lbenzene resulted in decreased degradative ability. The cell-specific growth rates on ethylbenzene conformed to the Haldane–Andrew model in the substrate level range of 10–150 mg L^?1. Kinetic parameters were determined by nonlinear regression on specific growth rates and various initial substrate concentrat-ions, and the values of the maximum specific growth rate, half saturation constant, and inhibition constant were 0.71 day^?1, 34.3 mg L^?1, and 183.5 mg L^?1, respectively. This is the first report of ethylbenzene biodegradation by a bacterium of Microbacterium lacticum under nitrate-reducing conditions.     

Rapid and efficient degradation of bisphenol A by chloroperoxidase from <Emphasis Type="Italic">Caldariomyces fumago</Emphasis>: product analysis and ecotoxicity evaluation of the degraded solution

Objectives

To degrade enzymatically bisphenol A (BPA) that causes serious environmental concerns and is difficult to be degraded by chemical or physical methods.

Results

BPA (150 mg l^?1) was completely degraded by chloroperoxidase (CPO)/H₂O₂ within 7 min at room temperature, atmospheric pressure with the enzyme at 6 μg CPO ml^?1. The degradation products were identified by HPLC–MS, which suggested involvement of multiple steps. Enzymatic treatment followed by existing bioremediation technologies (activated sludge) enhanced removal of COD from 9 to 54 %. Using an ecotoxicity evaluation with Chlorella pyrenoidosa, the degradation products had a lower toxicity than BPA.

Conclusion

BPA can be degraded rapidly and efficiently under mild conditions with chloroperoxidase at 6 μg ml^?1. The degradation products had a lower toxicity than BPA.

     

Promoting effects of organic medium supplements on the micropropagation of promising ornamental Daphne species (Thymelaeaceae)

Three Daphne species (Thymelaeaceae) were propagated in vitro using media enriched with natural ingredients including coconut water, pineapple pulp, arabinogalactan, chitosan, and conditioned medium containing exudates of the green alga Desmodesmus subspicatus. High vigor of proliferative shoots and enhanced rooting efficiency were obtained. The propagation rate for shoot cultures of Daphne caucasica and Daphne tangutica increased significantly when cultured in the presence of 10 ml?L^?1 coconut water or 10 ml?L^?1 pineapple pulp. Addition of 10 ml?L^?1 pineapple pulp, 10 ml?L^?1 coconut water, or 20% conditioned medium to the culture medium stimulated organogenesis in D. caucasica. The percentage of rooted shoots in this difficult-to-root species reached 80% in enriched medium. Daphne jasminea plants rooted efficiently on media without growth regulators but supplemented with 10 ml?L^?1 pineapple pulp or 10 ml?L^?1 coconut water. Plants of D. caucasica and D. jasminea were successfully acclimatized to greenhouse conditions. Biochemical evaluation of pineapple pulp using thin-layer chromatography revealed the absence of natural auxins. However, the low-molecular-weight fraction (<500 Da) obtained via dialysis significantly stimulated rhizogenesis in each species tested.     

Efficacy of Acinetobacter sp. B9 for simultaneous removal of phenol and hexavalent chromium from co-contaminated system

The present study shows the feasibility of a newly isolated strain Acinetobacter sp. B9 for concurrent removal of phenol and Cr (VI) from wastewater. The experiments were conducted in a batch reactor under aerobic conditions. Initially, when mineral salt solution was used as the culture medium, the strain was found to utilize phenol as sole carbon and energy source while no Cr (VI) removal was observed. However, the addition of glucose as co-carbon source resulted in the removal of both toxicants. This co-removal efficiency of the strain was further improved with nutrient-rich media (NB). Optimum co-removal was determined at 188 mg L^?1 of phenol and 3.5 mg L^?1 of Cr (VI) concentrations at pH 7.0. Strain B9 followed the orthometabolic pathway for phenol degradation. Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) studies showed sorption of chromium as one of the major mechanisms for Cr (VI) removal by B9 cells. Acinetobacter sp. B9 was later on checked for bioremediation of real tannery wastewater. After 96 h of batch treatment of tannery effluent containing an initial 47 mg L^?1 phenol and 16 mg L^?1 Cr (VI), complete removal of phenol and 87 % reduction of Cr (VI) were attained, showing high efficiency of the bacterial strain for potential application in industrial pollution control.     

Co-generation of ethanol and <Emphasis Type="SmallCaps">l</Emphasis>-lactic acid from corn stalk under a hybrid process

Background

Corn stover, as one important lignocellulosic material, has characteristics of low price, abundant output and easy availability. Using corn stover as carbon source in the fermentation of valuable organic chemicals contributes to reducing the negative environmental problems and the cost of production. In ethanol fermentation based on the hydrolysate of corn stover, the conversion rate of fermentable sugars is at a low level because the native S. cerevisiae does not utilize xylose. In order to increase the conversion rate of fermentable sugars deriving from corn stover, an effective and energy saving biochemical process was developed in this study and the residual xylose after ethanol fermentation was further converted to l-lactic acid.

Results

In the hybrid process based on the hydrolysate of corn stover, the ethanol concentration and productivity reached 50.50 g L^?1 and 1.84 g L^?1 h^?1, respectively, and the yield of ethanol was 0.46 g g^?1. The following fermentation of l-lactic acid provided a product titer of 21.50 g L^?1 with a productivity of 2.08 g L^?1 h^?1, and the yield of l-lactic acid was 0.76 g g^?1. By adopting a blank aeration before the inoculation of B. coagulans LA1507 and reducing the final cell density, the l-lactic acid titer and yield reached 24.25 g L^?1 and 0.86 g g^?1, respectively, with a productivity of 1.96 g L^?1 h^?1.

Conclusions

In this work, the air pumped into the fermentor was used as both the carrier gas for single-pass gas stripping of ethanol and the oxygen provider for the aerobic growth of B. coagulans LA1507. Ethanol was effectively separated from the fermentation broth, while the residual medium containing xylose was reused for l-lactic acid production. As an energy-saving and environmental-friendly process, it introduced a potential way to produce bioproducts under the concept of biorefinery, while making full use of the hydrolysate of corn stover.

     

Evaluation of an electronic nose for the early detection of organic overload of anaerobic digesters

This study aimed at analysing the utilization of an electronic nose (e-nose) to serve as a specific monitoring tool for anaerobic digestion process, especially for detecting organic overload. An array of non specific metal oxide semiconductor gas sensors were used to detect process faults due to organic overload events in twelve 1.8-L anaerobic semi-continuous reactors. Three different load strategies were followed: (1) a cautious organic load (1.3 gVS L^?1 day^?1); (2) an increasing load strategy (1.3–5.3 gVS L^?1 day^?1) and (3) a cautious organic load with load pulses of up to 12 gVS L^?1 day^?1. A first monitoring campaign was conducted with three different substrates: sucrose, maize oil and a mix of sucrose/oil during 60 days. The second campaign was run with dry sugar beet pulp for 45 days. Hotelling’s T ² value and upper control limit to a reference set of digesters fed with a cautious OLR (1.3 gVS L^?1 day^?1) was used as indirect state variable of the reactors. Overload situations were identified by the e-nose apparatus with Hotelling’s T ² values at least four times higher in magnitude than the upper control limit of 23.7. These results confirmed that the e-nose technology appeared promising for online detection of process imbalances in the domain of anaerobic digestion.     

Citric acid production from extract of Jerusalem artichoke tubers by the genetically engineered yeast Yarrowia lipolytica strain 30 and purification of citric acid

In this study, citric acid production from extract of Jerusalem artichoke tubers by the genetically engineered yeast Yarrowia lipolytica strain 30 was investigated. After the compositions of the extract of Jerusalem artichoke tubers for citric acid production were optimized, the results showed that natural components of extract of Jerusalem artichoke tubers without addition of any other components were suitable for citric acid production by the yeast strain. During 10 L fermentation using the extract containing 84.3 g L^?1 total sugars, 68.3 g L^?1 citric acid was produced and the yield of citric acid was 0.91 g g^?1 within 336 h. At the end of the fermentation, 9.2 g L^?1 of residual total sugar and 2.1 g L^?1 of reducing sugar were left in the fermented medium. At the same time, citric acid in the supernatant of the culture was purified. It was found that 67.2 % of the citric acid in the supernatant of the culture was recovered and purity of citric acid in the crystal was 96 %.     

The effectiveness of the high-LET radiations from the boron neutron capture [<Superscript>10</Superscript>B(n,α)<Superscript>7</Superscript>Li] reaction determined for induction of chromosome aberrations and apoptosis in lymphocytes of human blood samples

Provided that a selective accumulation of ¹⁰B-containing compounds is introduced in tumor cells, following irradiation by thermal neutrons produces high-LET alpha-particles (⁴He) and recoiling lithium-7 (⁷Li) nuclei emitted during the capture of thermalized neutrons (0.025 eV) from ¹⁰B. To estimate the biological effectiveness of this boron neutron capture [¹⁰B(n,α)⁷Li] reaction, the chromosome aberration assay and the flow cytometry apoptosis assay were applied. At the presence of the clinically used compounds BSH (sodium borocaptate) and BPA (p-boronophenylalanine), human lymphocytes were irradiated by sub-thermal neutrons. For analyzing chromosome aberrations, human lymphocytes were exposed to thermally equivalent neutron fluences of 1.82 × 10¹¹ cm^?2 or 7.30 × 10¹¹ cm^?2 (corresponding to thermal neutron doses of 0.062 and 0.248 Gy, respectively) in the presence of 0, 10, 20, and 30 ppm of BSH or BPA. Since the kerma coefficient of blood increased by 0.864 × 10^?12 Gy cm² per 10 ppm of ¹⁰B, the kerma coefficients in blood increase from 0.34 × 10^?12 cm² (blood without BSH or BPA) up to 2.93 × 10^?12 Gy cm² in the presence of 30 ppm of ¹⁰B. For the ¹⁰B(n, α)⁷Li reaction, linear dose–response relations for dicentrics with coefficients α = 0.0546 ± 0.0081 Gy^?1 for BSH and α = 0.0654 ± 0.0075 Gy^?1 for BPA were obtained at 0.062 Gy as well as α = 0.0985 ± 0.0284 Gy^?1 for BSH and α = 0.1293 ± 0.0419 Gy^?1 for BPA at 0.248 Gy. At both doses, the corresponding ¹⁰B(n, α)⁷Li reactions from BSH and BPA are not significantly different. A linear dose–response relation for dicentrics also was obtained for the induction of apoptosis by the ¹⁰B(n, α)⁷Li reaction at 0.248 Gy. The linear coefficients α = 0.0249 ± 0.0119 Gy^?1 for BSH and α = 0.0334 ± 0.0064 Gy^?1 for BPA are not significantly different. Independently of the applied thermal neutron doses of 0.062 Gy or 0.248 Gy, the ¹⁰B(n, α)⁷Li reaction from 30 ppm BSH or BPA induced an apparent RBE of about 2.2 for the production of dicentrics as compared to exposure to thermal neutrons alone. Since the apparent RBE value is defined as the product of the RBE of a thermal neutron dose alone times a boron localization factor which depends on the concentration of a ¹⁰B-containing compound, this localization factor determines the biological effectiveness of the ¹⁰B(n, α)⁷Li reaction.     

Soil carbon stocks and quality across intact and degraded alpine wetlands in Zoige,east Qinghai-Tibet Plateau

The wetlands on the Qinghai-Tibet Plateau are experiencing serious degradation, with more than 90,000 hectares of marshland converted to wet meadow or meadow after 40 years of drainage. However, little is known about the effects of wetland conversion on soil C stocks and the quality of soil organic carbon (SOC) (defined by the proportion of labile versus more resistant organic carbon compounds). SOC, microbial biomass carbon, light fraction organic carbon (LFOC), dissolved organic carbon, and the chemical composition of SOC in the soil surface layer (0–10 cm), were investigated along a wetland degradation gradient (marsh, wet meadow, and meadow). Wetland degradation caused a 16 % reduction in the carbon stocks from marsh (178.7 ± 15.2 kg C m^?2) to wet meadow (150.6 ± 21.5 kg C m^?2), and a 32 % reduction in C stocks of the 0–10 cm soil layer from marsh to meadow (122.2 ± 2.6 kg C m^?2). Wetland degradation also led to a significant reduction in SOC quality, represented by the lability of the carbon pool as determined by a density fractionation method (L _LFOC), and a significant increase in the stability of the carbon pool as reflected by the alkyl-C:O-alkyl-C ratio. ¹³C NMR spectroscopy showed that the labile form of C (O-alkyl-C) declined significantly after wetland degradation. These results assist in explaining the transformation of organic C in these plateau wetland soils and suggest that wetland degradation not only caused SOC loss, but also decreased the quality of the SOC of the surface soil.     

Kinetics of the aerobic co-metabolism of 1,1-dichloroethylene by Achromobacter sp.: a novel benzene-grown culture

Batch experiments were performed for the aerobic co-metabolism of 1,1-dichloroethylene (1,1-DCE) by Achromobacter sp., identified by gene sequencing of 16S rRNA and grown on benzene. Kinetic models were employed to simulate the co-metabolic degradation of 1,1-DCE, and relevant parameters were obtained by non-linear least squares regression. Benzene at 90 mg L^?1 non-competitively inhibited degradation of 1,1-DCE (from 125 to 1,200 μg L^?1). The maximum specific utilization (k_c) rate and the half-saturation constant (K_c) for 1,1-DCE were 54 ± 0.85 μg h^?1 and 220 ± 6.8 μg L^?1, respectively; the k_b and K_b for benzene were 13 ± 0.18 mg h^?1 and 28 ± 0.42 mg L^?1, respectively. This study provides a theoretical basis to predict the natural attenuation when benzene and 1,1-DCE occur as co-contaminants.     

Biodegradation of tributyl phosphate using Klebsiella pneumoniae sp. S3

Tributyl phosphate (TBP) has enormous applications in the field of extraction, fuel reprocessing, as defoamers and/or plasticizers. Excessive usage of this organophosphorus compound, poses an environmental threat. The present study deals with microbial degradation of TBP using Klebsiella pneumoniae S3 isolated from the soil. Diauxic growth curve pattern explains a preferential utilization of TBP. The strain S3 was able to biotransform TBP (1,000 mg L^?1) to dibutyl phosphate within 48 h and showed higher tolerance towards TBP up to 17.0 g L^?1. Toxicity of the parent as well as degraded product was assessed using comet assay. Generation of reactive oxygen species elaborates the oxidative stress imposed upon the bacterial strain by TBP. The antioxidant defense mechanism was studied using various biomarkers namely catalase, glutathione-S-transferase, and superoxide dismutase. The present study describes a faster and eco-friendly alternative for disposal of TBP.     

Complete and simultaneous removal of ammonium and m-cresol in a nitrifying sequencing batch reactor

The kinetic behavior, oxidizing ability and tolerance to m-cresol of a nitrifying sludge exposed to different initial concentrations of m-cresol (0–150 mg C L^?1) were evaluated in a sequencing batch reactor fed with 50 mg NH₄ ⁺-N L^?1 and operated during 4 months. Complete removal of ammonium and m-cresol was achieved independently of the initial concentration of aromatic compound in all the assays. Up to 25 mg m-cresol-C L^?1 (C/N ratio of 0.5), the nitrifying yield (Y-NO₃ ^?) was 0.86 ± 0.05, indicating that the nitrate was the main product of the process; no biomass growth was detected. From 50 to 150 mg m-cresol-C L^?1 (1.0 ≤ C/N ≤ 3.0), simultaneous microbial growth and partial ammonium-to-nitrate conversion were obtained, reaching a maximum microbial total protein concentration of 0.763 g L^?1 (247 % of its initial value) and the lowest Y-NO₃ ^? 0.53 ± 0.01 at 150 mg m-cresol-C L^?1. m-Cresol induced a significant decrease in the values of both specific rates of ammonium and nitrite oxidation, being the ammonium oxidation pathway the mainly inhibited. The nitrifying sludge was able to completely oxidize up to 150 mg m-cresol-C L^?1 by SBR cycle, reaching a maximum specific removal rate of 6.45 g m-cresol g^?1 microbial protein-N h^?1. The number of SBR cycles allowed a metabolic adaptation of the nitrifying consortium since nitrification inhibition decreased and faster oxidation of m-cresol took place throughout the cycles.     

Culture Media Statistical Optimization for Biomass Production of a Ligninolytic Fungus for Future Rice Straw Degradation

The main objective of this study was to optimize a culture media for low scale biomass production of Pleurotus spp. Future applications of this optimization will be implemented for “in situ” rice straw degradation, increase soil nutrients availability, and lower residue and rice culture management costs. Soil samples were taken from different points in six important rice production cities in Colombia. For carbon and nitrogen source selection a factorial 4² design was carried out. The Plackett-Burman design permitted to detect carbon, nitrogen and inducer effects on fungus growth (response variable for all designs). This optimization was carried out by a Box-Behnken design. Finally a re-optimization assay for glucose concentration was performed by means of a One Factor design. Only 4/33 (12 %) isolates showed and important laccase or manganese peroxidase activity compared to Pleurotus ostreatus (HPB/P3). We obtained an increased biomass production in Pleurotus spp. (T1.1.) with glucose, followed by rice husk. Rice straw was considered an inducing agent for lignin degradation. Glucose was a significant component with positive effects, whereas Tween 80 and pH had negative effects. On the contrary, rice husk, yeast extract and CaCl₂ were not significant components for increase the biomass production. Final media composition consisted of glucose 25 g L^?1, yeast extract 5 g L^?1, Tween 80 0.38 % (v/v), Rice husk 10 g L^?1, CaCl₂ 1 g L^?1, and pH 4.88 ± 0.2. The Box-Behnken polynomial prediction resulted to be lower than the experimental validation of the model (6.59 vs. 6.91 Log₁₀ CFU ml^?1 respectively).     

Optimization of culture conditions for the production of polysaccharides and kinsenoside from the rhizome cultures of <Emphasis Type="Italic">Anoectochilus roxburghii</Emphasis> (Wall.) Lindl.

The present study designed two sets of experiments by using the uniform design method and investigated the effects of medium components on the accumulation of bioactive compounds (polysaccharide and kinsenoside) in rhizomes, in order to select a suitable culture medium for the rhizome suspension culture of Anoectochilus roxburghii (Wall.) Lindl. Among the combinations of Murashige and Skoog (MS) medium strengths and plant growth regulator (benzylaminopurine, BA; kinetin, KT; and α-naphthaleneacetic acid, NAA) concentrations, and the combinations of nitrogen, phosphorus, and sucrose concentrations, the maximum yield of polysaccharides and kinsenoside was achieved with 0.75 × MS?+?2.0 mg L^?1 BA?+?0.2 mg L^?1 KT?+?0.5 mg L^?1 NAA and 45 mM nitrogen?+?0.93 mM phosphorus?+?35 g L^?1 sucrose, respectively. Therefore, the optimal rhizome suspension culture medium was 0.75 × MS medium supplemented with 2.0 mg L^?1 BA, 0.2 mg L^?1 KT, 0.5 mg L^?1 NAA, and 35 g L^?1 sucrose. Yeast extract (YE) enhanced bioactive compound accumulation in rhizomes. The polysaccharide and kinsenoside production was significantly improved when 75 mg L^?1 YE was added to the culture medium after 30 d of rhizome suspension culture; 8.3 g L^?1 of polysaccharide and 6.1 g L^?1 of kinsenoside were obtained after 4 d of YE treatment. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of YE-treated rhizomes was higher than that of YE-untreated rhizomes, demonstrating enhanced antioxidant activity of the treated bioreactor-cultured rhizomes.