Papers by Keyword: Detoxification

Abstract: The fuel butanol yield and productivity obtained during fermentation of lignocellulosic hydrolysates is decreased due to the presence of inhibiting compounds, such as carboxylic acids, phenolic compounds and furans formed during hydrolysis. The main objective of this work is to evaluate the biological detoxification method of lignocellulosic hydrolysates when two forms of specially adapted activated sludge are used for improved biobutanol production. We investigated the removal of toxic substances from an enzymatic hydrolysate of miscanthus cellulose and an acid hydrolysate of spruce by specially adapted activated sludge of the urban wastewater treatment plants and by activated sludge of the pig farm wastewater treatment plants. Activated sludge treatment removed 98 % and 99 % of 5-hydroxymethylfurfural (5-HMF) and furfural from the hydrolysate respectively. Fermentation of treated hydrolysates by Clostridium acetobutylicum ATCC 824 was successful. Control experiments on fermentation of untreated hydrolysates showed a complete absence of fermentation

Abstract: The effects of a solid waste containing Cr (VI) (SWCC) detoxified with orange peel (OP) and pineapple peel (PP) on the development of seeds were investigated. The results show that PP does better than OP. In the composites of PP, SWCC and soils, all the tested seeds (peanut, maize, green Chinese cabbage, soybean and garlic) grow if SWCC content is lower than 10%. The seeds, however, indicated variant resistance to SWCC, and garlic behaved best. It is possible to grow vegetables or plants with the composites of biomass, SWCC and soils, but it is also necessary to optimize the proportions for each of the kinds.

Abstract: Samples of anaerobically digested sludges from municipal wastewater treatment installations containing several toxic heavy metals (Cu, Zn, Ni, Co, Cr, Mn, Fe), different organochemicals and biological pollutants (mainly bacteria of the genera Escherichia, Klebsiella, Streptococcus and Clostridium) were subjected to different procedures for detoxification to make possible their use in agriculture. It was found that the bioleaching of these sludges at 70 °C by mixed cultures of extremely thermophilic chemolithotrophic bacteria was the most efficient way to decrease below the relevant permissible levels all above-mentioned pollutants. The bioleaching was carried out in reactors with mechanical stirring and enhanced aeration (by CO₂ enriched air) under batch and continuous-flow conditions. The extraction of some metals (mainly of Cu and Zn) which were present in relatively high concentrations in some sludge samples was very efficient and exceeded 90 % within residence times of about 96 - 120 hours. The dissolved copper and zinc were recovered from the pregnant solutions after bioleaching by means of solvent extraction plus electrolysis. At the same time, the bioassimilable forms of N, P, K and the essential microelements were still present in sufficient concentrations in the pretreated sludges making them suitable for use in agriculture. This was confirmed by experiments in green-houses with plants intended for use in the bioremediation of post-mining landscapes.

Abstract: Maize (Zea mays L.) is one of the main cereals as a source of food, forage and processed products for industry, especially for feeds. However, in worldwide approximately 25% of crops are affected by mycotoxins annually, especially in feeds with fumonisins(FUM). Moreover, the exact mechanism of FUM toxicity is not completely established. This paper gives an overview about the occurrence, toxicity, rapid non-invasive analysis, and detoxification of FUM in maize and its feeds. Due to economic losses engendered by FUM and its impact on animal and human health, several strategies for detecting mycotoxins with non-invasive methods and detoxifying contaminated feeds have been described.

Abstract: Corn straw from steam-explosion treatment process was treated with different organic solvents to reduce the inhibition for the sequent enzymatic hydrolysis and fermentation. The detoxified substrates (100 g DW/L) were hydrolyzed with a blend of Novozym 188 (15 IU/g cellulose), Celluclast CP cellulase (15 FPU/g cellulose) and lignase (15 IU/g hemicellulose). The reducing sugar was bio-converted to ethanol with separated hydrolysis and fermentation processes using Pachysolen tannophilus P-01. The reducing sugar yield varied from 34.8 to 89.7% depending on the detoxification solvents and modes. The highest ethanol yield (96.1% of theoretical value) was obtained with the combined extraction of ether and acetone.

Abstract: Chromium-containing slag is one of the most hazardous solid waste because of the high content of dissolvable Cr (VI). Bacterial strains which can remove Cr (VI) efficiently were isolated from chromium-containing slag. The effect of processing parameters, such as quantity of chromium-containing slag, initial pH, temperature and agitation speed on the detoxification of chromium-containing slag were detected in the experiment. The results shows that the detoxification effect is reduced along with the quantity of chromium-containing slag is increased, and the optimized parameters for removing Cr (VI) from chromium-containing slag using the mixed strains are as follows: temperature = 30°C, pH = 7.0, agitation speed = 150 rpm. The detoxification experiments of the mixed strains indicated that the detoxification of chromium-containing slag is related to the growth law of the microorganisms, and the removal of Cr (VI) occurred primarily in the first 24h which is the exponential growth period of the mixed strains. At the same time, the bacterial strains can efficiently accelerate Cr (VI) leaching rate and remove it.

Abstract: Xylitol can be obtained from hemicelullosic fraction of lignocellulosic materials containing D-xylose. Formic acid hydrolysis is widely used in lignocellulose pretreatment. However, formic acid hydrolysis wheat straw cannot be directly used as fermentation subsequently owing to various fermentation inhibitors, especially the formic acid in reaction system and released during pretreatment. This study describes main hydrolysis components and inhibitors prepared by hydrolysis of wheat straw with formic acid solution, and different detoxification methods ware used to romve the inhibitors. Study found treatment of wheat straw hydrolysate with overliming treatment and D311 ion-exchange resin had a good result on reduction formic acid and other main inhibitors, results showed which can eliminate 94% of residual formic acid and with only 15% reducion of xylose. To verify the effectiveness of different detoxification methods, hydrolysates of detoxification werr fermented by Candida.tropicalis AS2.1776, and the results also found that the hydrolysate treatmented with overliming treatment and D311 ion-exchange resin have the hightest xylitol yield.

Abstract: Eight swainsonine (SW)-degrading bacteria were isolated from the soil where locoweed was buried for 6 months and one of the strains (YLZZ-2) was selected for further study. Based on morphology, physiologic tests, 16S rDNA sequence, and phylogenetic characteristics, the strain showed the greatest similarity to members of the order Stenotrophomonap and the closest to members of the Stenotrophomonas maltophilia group. The ability of the strain to degrade SW, as sole carbon source, was investigated under different culture conditions. The preferential temperature and initial pH value for the strain were 25～35 °C and 6.0～9.0, respectively. The optimal temperature for the strain was 30 °C and the optimal pH value was 7.0. There was positive correlation between degradation rate and inoculation amount. The growth of stain YLZZ-2 and degradation rate were fast, and YLZZ-2 could completely degradate 400 mg/L swainsoine within 24 h. There was a linear relationship between the growth of stain YLZZ-2 and degradation of swainsonine. These results highlight the potential of this bacterium to be used in detoxifying of SW in livestock consuming locoweed.

Abstract: For ages, activated carbon has been unarguably the most preferred material for chemical warfare protective clothing by armies across the globe. Although the morphology in which it is used has changed from granular form to fiber form, there has not been much change in the chemical composition or functionality (ASZM-TEDA grade). In this paper we investigate to find out if there is a possibility of replacement of the activated carbon by other materials. Before we find the answer to this question, it is important to reason out why replacement is thought of in the first place. Activated carbon is a versatile material that brings with it several good qualities like large surface area, adsorptive nature, fire-resistant, robustness and availability of aplenty. Some of its disadvantages include heavy weight and low breathability (moist activated carbon will adsorb oxygen from the environment causing breathing difficulties). One other disadvantage which is often overlooked by the user is the disposal of the suits after usage. Activated carbon merely adsorbs the nerve and mustard agents and once they become saturated, they are classified as hazardous materials necessitating safe disposal. The used wear is normally sent back to the supplier of manufacturer where it would be essentially decontaminated by bleaching and then disposed by incineration or landfill. Thus, if there is a material that can ensure breathability is of light weight and has the capacity to decontaminate the adsorbed warfare agents in situ, it would be ideal for use in the protective clothing. In this paper novel electrospun ceramic nanostructures are introduced which are capable of reactive decontamination of nerve and mustard agents. The decontamination efficiencies of the ceramic nanofibers are presented as tested against simulants of nerve and mustard agents. Electrospinning was chosen as the fabrication method because it is a simple traditional technique that is capable of manufacturing nano sized structures in a large scale. Moreover, electrospun materials possess more activity due to their surface charge density. The contribution of nano-size scale to the reactivity of the fibers is shown. All these project the electrospun nanostructured ceramics as the best possible substitutes to activated carbon.

Abstract: AflatoxinB1 was extracted from rice contaminated artificially with Aspergillus flavus by using methanol-water (50:50 v/v). As for experiment group, sodium chloride was added into the extracted solution of AfB1, the excitation wavelength of 365 nm under the fluorescence mode, and the emission spectrum peak at 440nm were observed. To study the detoxification of AflatoxinB1 in several alkaline solutions, the solution of alkaline with difference concentration was added into the solution of AfB1 respectively. The results showed that all of three alkaline solutions could decrease the 440nm emission spectrum peak of solution of AfB1 in varying degrees, the effect to decrease emission spectrum peak of AfB1 was very obvious in sodium hypochlorite (NaClO), and sodium hydroxide (NaOH) took second place, whereas in ammonia (NH3·H2O), the effect was the weakest among three alkaline solutions. Moreover, the effects were different in the same alkaline solutions with different concentration, as hydrochloric acid (HCl) in low concentration was added to this complex AfB1 alkaline solutions, detoxification efficacy of AfB1 were found to be obviously increased. It was concluded that the detoxification of AflatoxinB1 may be affected by alkaline solutions according to their concentration and be degraded greatly by acid addition.