Activated Charcoal Treatment Research Articles

Activated charcoal for GHB intoxication: An in vitro study

ContextIntoxications with gamma-hydroxybutyrate (GHB) are occurring more frequently. Patients are primarily treated symptomatically. The use of activated charcoal (AC) has been suggested in several guidelines and in literature, although the clinical value of AC in GHB intoxication is a matter of debate. However, it has never been demonstrated that GHB binds to AC. Under certain conditions, prevention of absorption could be clinically relevant. Therefore, adsorption of GHB to AC in an in vitro model was tested. Materials and methodsA previously described in vitro model was used. Dosages of 2.5, 5, 7.5, or 10g of standard AC (simulating in vivo dosages of approximately 25–100g) were mixed with a dose of 800mg GHB at 37°C in 100mL simulated gastric or intestinal fluid, respectively. Subsequently, the AC was separated from the liquid by centrifugation and the remaining GHB quantified by gas chromatography. GHB adsorption capacity was plotted in an adsorption curve. ResultsBinding of GHB to AC was dose-dependent. At gastric pH, adsorption was higher than at intestinal pH, with a maximum adsorption of 84.3% and 23.3%, respectively, with 10g of AC, corresponding with a high adult dose. Discussion and conclusionAC has clinically relevant GHB binding capacity, which is pH dependent. The normally rapid adsorption and the need for intubation argue against AC treatment in GHB intoxications. However, under certain circumstances e.g. in case of unintentional intake of GHB by children or in case of very high doses of GHB, rapid treatment with AC may still be appropriate. In vivo studies are needed to establish the clinical relevance of GHB adsorption to AC.

Evaluation of ethanol production by a new isolate of yeast during fermentation in synthetic medium and sugarcane bagasse hemicellulosic hydrolysate

A new xylose fermenting yeast was isolated from over-ripe banana by enrichment in xylose-containing medium. The phylogenetic analysis of ITS1-5.8S-ITS2 region sequences of ribosomal RNA of isolate BY2 revealed that it shows affiliation to genus Pichia and clades with Pichia caribbica. In batch fermentation, Pichia strain BY2 fermented xylose, producing 15 g l−1 ethanol from 30 g l−1 xylose under shaking conditions at 28°C, with ethanol yield of 0.5 g g−1 and volumetric productivity of 0.31 g l−1 h−1. The optimum pH range for ethanol production from xylose by Pichia strain BY2 was 5–7. Pichia strain BY2 also produced 6.08 g l−1 ethanol from 30 g l−1 arabinose. Pichia strain BY2 can utilize sugarcane bagasse hemicellulose acid hydrolysate for alcohol production, efficiency of fermentation was improved by neutralization, and sequential use of activated charcoal adsorption method. Percent total sugar utilized and ethanol yield for the untreated hydrolysate was 17.14% w/v and 0.33 g g−1, respectively, compared with 66.79% w/v and 0.45 g g−1, respectively, for treated hemicellulose acid hydrolysate. This new yeast isolate showed ethanol yield of 0.45 g g−1 and volumetric productivity of 0.33 g l−1 h−1 from sugarcane bagasse hemicellulose hydrolysate detoxified by neutralization and activated charcoal treatment, and has potential application in practical process of ethanol production from lignocellulosic hydrolysate.

Increased unbound drug fraction in acute carbamazepine intoxication: suitability and effectiveness of high-flux haemodialysis

Dear Editor, A 61-year-old woman (patient A) was admitted to our intensive care unit with carbamazepine overdose. Carbamazepine total plasma concentration determined by enzyme-multiplied immunoassay technique (EMIT) was 52.5 mg/L (reference 4–12 mg/L) of which 22.7 mg/L was unbound (43%). Unbound carbamazepine was determined in plasma by EMIT after ultrafiltration (Amicon Ultra centrifugal filter (Millipore), 2,500 rpm, 30 min at 25°C). Despite supportive care (pacemaker, inotropes and vasopressors) and multiple activated charcoal administration, the patient died shortly after admission as a result of refractory shock. Soon after, a 41-year-old man (patient B) was admitted after resuscitation due to ventricular fibrillation. For epilepsy he was treated with carbamazepine (400 mg 5 times/day). As a result of repeated ventricular fibrillation, intravenous amiodarone (300 mg/day) was started. Two days later a deep coma developed. Because of a high daily dose of carbamazepine and its interaction with amiodarone, we suspected a carbamazepine intoxication. Total carbamazepine plasma concentration was 27.4 mg/L of which 10.9 mg/L was unbound (40%). Carbamazepine intoxication was treated with multiple-dose activated charcoal and high-flux haemodialysis (HF-HD); filter Fresenius Helixon® FX1000, blood flow 350 mL/min, dialysate flow 500 mL/min, ultrafiltration rate 120 mL/h, ultrafiltration coefficient 75 mL/(h mmHg). Carbamazepine plasma concentration decreased to 13.0 mg/L (4.1 mg/L unbound; 32%) (Fig. 1). The patient fully recovered. Fig. 1 Carbamazepine total (solid circles) and unbound (open circles) plasma concentrations in patient B. Therapeutic range for total plasma concentrations 4–12 mg/L Treatment of carbamazepine intoxication consists of supportive care, prevention of further absorption and enhancement of elimination via haemoperfusion [1, 2]. But haemoperfusion has serious adverse effects and the facilities are often not available [1, 3]. Effectiveness of haemodialysis depends on drug characteristics, dialysis system properties and dialysis conditions. Haemodialysis in carbamazepine overdose is considered not to be efficacious because of low hydrophilicity (Log P = 1.98) and the high degree of protein binding (70–80%), although carbamazepine is small enough for filtration (236 Da) and has a low distribution volume (0.8–1.8 L/kg) [1]. Elimination rate constants (k), calculated as k = ln 2/half-life (h), reflect the effectiveness of the elimination route. Overall k is defined as the sum of all individual k values. Calculated individual k values in patient B were 0.009/h for endogenous metabolism, 0.059/h for dialysis (including membrane adsorption) and 0.039/h for charcoal treatment. Endogenous k was calculated from the time period in which no activated charcoal or HF-HD was applied. k of activated charcoal was calculated by subtracting k endogenous from k overall when only endogenous clearance and activated charcoal therapy were present. k dialysis is k overall during HF-HD minus k endogenous and k activated charcoal. Limited blood sampling during the initial rapid clearance of free drug from the plasma by HF-HD may partly hamper the interpretation of the results. However, on the basis of the half-life initially and later on during HF-HD, we assume that no significant rapid initial phase took place (see Fig. 1). HF-HD was more effective than multiple activated charcoal treatment alone, whereas the combination of both was about ten times more effective than endogenous clearance. Probably, endogenous k was decreased because of the presence of amiodarone, a CYP3A4 inhibitor [4]. Owing to the increased unbound drug concentration in carbamazepine intoxication, HF-HD proved to be an effective extracorporeal elimination technique. In conclusion, HF-HD is an effective extracorporeal elimination technique in carbamazepine intoxication as a result of the increased unbound drug fraction and can replace haemoperfusion.

Overcoming inhibitors in a hemicellulosic hydrolysate: improving fermentability by feedstock detoxification and adaptation of Pichia stipitis

In order to improve the fermentative efficiency of sugar maple hemicellulosic hydrolysates for fuel ethanol production, various methods to mitigate the effects of inhibitory compounds were employed. These methods included detoxification treatments utilizing activated charcoal, anion exchange resin, overliming, and ethyl acetate extraction. Results demonstrated the greatest fermentative improvement of 50% wood hydrolysate (v/v) by Pichia stipitis with activated charcoal treatment. Another method employed to reduce inhibition was an adaptation procedure to produce P. stipitis stains more tolerant of inhibitory compounds. This adaptation resulted in yeast variants capable of improved fermentation of 75% untreated wood hydrolysate (v/v), one of which produced 9.8g/l±0.6 ethanol, whereas the parent strain produced 0.0g/l±0.0 within the first 24h. Adapted strains RS01, RS02, and RS03 were analyzed for glucose and xylose utilization and results demonstrated increased glucose and decreased xylose utilization rates in comparison to the wild type. These changes in carbohydrate utilization may be indicative of detoxification or tolerance activities related to proteins involved in glucose and xylose metabolism.

Comparative study on different strategies involved for xylitol purification from culture media fermented by Candida tropicalis

Xylitol, a sugar substitute, is a high value product for pharmaceutical and food industries and its purification being of commercial importance. In the present study, the purification of xylitol obtained through Candida tropicalis by fermentation using synthetic xylose and corn cob hemicellulosic hydrolysate as substrates were studied for liquid–liquid extraction (21.72 g/l xylitol extracted in 1:5 (v/v) of ethyl acetate) and precipitation (67.44% xylitol recovery along with certain impurities). By this method xylitol recovery is difficult and expensive for large scale processes. Therefore, activated charcoal treatment followed by vaccum concentration and crystallization method for xylitol extraction was evaluated. The optimized conditions obtained for activated charcoal treatment followed by vaccum concentration and crystallization method were 15.0 g/l of charcoal concentration at 30 °C for 1 h with 10 times super saturation of initial concentration and crystallization temperature of −20 °C for initiation and then at 8 °C yielding 43.97%. After 4 cycles of crystallization, 76.20% and 68.06% xylitol crystallization yield was obtained in 50 ml and 5.0 l of the synthetic xylose fermentation broth by adapted strain of C. tropicalis respectively. The effect of solvents on the crystalline structure of xylitol showed prismatic structure in the presence of ethanol and orthorhombic needles in the presence of tetrahydrofuran. The purity of the xylitol was characterized using 13C and 1H nuclear magnetic resonance, mass spectroscopy, and optical rotation, confirming 98.99% purity in a pure crystallized form.

Effect of activated charcoal treatment of alkaline hydrolysates from sugarcane bagasse on purification of p-coumaric acid

The brown compounds in the ultrafiltration permeates resulting from the alkaline-hydrolysis of sugarcane bagasse were determined to be composed mainly of lignin monomers. These monomers significantly influence the separation and purification of p-coumaric acid. Addition of 3% of activated charcoal removed 78.10% of the compounds’ color value but adsorbed only 14.36% of the available coumaric acid in alkaline conditions. Decoloration by the application of activated charcoal before purification by anion exchange chromatography ensured the repeated use of the resins and crystallization of p-coumaric acid, thus significantly reducing preparation costs. A total of 8.56 g of crystal contained 95.2% of coumaric acid was obtained from 1 kg of sugarcane bagasse after decoloration and separation.

Increased fermentability of enzymatically hydrolyzed steam-exploded corn stover for butanol production by removal of fermentation inhibitors

Acetone–butanol–ethanol (ABE) production from enzymatically hydrolyzed steam-exploded corn stover (SECS) by Clostridium acetobutylicum ATCC 824 was investigated in this study. Two methods to reduce fermentation inhibitors and thus increase fermentability were developed. An ABE yield of 0.15 and a productivity of 0.05g/(Lh) were obtained in the SECS hydrolysate (SECSH). This was lower compared to the yield of 0.23 and the productivity of 0.15g/(Lh) in the control medium containing 50g/L mixed sugars. Based on the composition analysis of SECSH, soluble lignin compounds (SLC) were found to be the main fermentation inhibitors. The ABE fermentation was inhibited when SLC exceeded to 1.77g/L in the SECSH-based medium. In contrast, fermentation was improved when SLC was less than 0.89g/L. To reduce the SLC concentration in SECSH, activated charcoal treatment was adopted to adsorb SLC from SECSH. To reduce inhibitor generation during the hydrolysis, alkaline peroxide treatment was used to remove the lignin from SECS. Batch fermentation of the two hydrolysates treated with the above methods resulted in an ABE yield of 0.30 and a productivity of 0.17g/(Lh). This indicates that the two established methods for the removal of inhibitors can enhance the fermentability of SECS in ABE production.

Impact of Fining on Chemical and Sensory Properties of Washington State Chardonnay and Gewürztraminer Wines

The impact of fining on the sensory and chemical properties of Washington State white wine was investigated. Unfined, commercially prepared Chardonnay and Gewürztraminer wines were treated with bentonite (1000 mg/L), isinglass (60 mg/L), Sparkalloid (360 mg/L), activated charcoal (450 mg/L), whole milk (500 mg/L), or wheat gluten (400 mg/L). Ethyl dodecanoate was the only volatile compound to significantly differ among Chardonnay treatments, which was highest in the control (0.031 mg/L) and lowest in Chardonnay treated with bentonite (0.017 mg/L). Conversely, a number of volatile compounds varied significantly among Gewürztraminer treatments. Ethyl acetate was significantly highest in the activated charcoal treatment (25.4 mg/L), while lowest in the Sparkalloid treatment (22.1 mg/L). In addition, Gewürztraminer treated with activated charcoal contained high concentrations of higher alcohols. Wheat gluten significantly decreased the concentrations of 1-hexanol, 3-methyl-1-butanol acetate, and 2-methyl-1-butanol. Benzeneethanol was significantly lower in the Sparkalloid, wheat gluten, and bentonite treatments. Conversely, benzeneethanol was highest in the isinglass (85.2 mg/L) and activated charcoal (74.7 mg/L) treatments. 2-Phenylethyl acetate and linalool were lowest in Gewürztraminer fined with bentonite. No significant differences were found among treatments for either varietal when the wines were subjected to difference testing (duo-trio) by an untrained panel (<i>p</i> ≥ 0.05). No differences were found among Gewürztraminer treatments evaluated by a trained panel, whereas differences in spicy aroma and floral/honey flavor were observed among Chardonnay treatments (<i>p</i> ≤ 0.05). This study demonstrated the impact fining can have on the chemical and sensory properties of wine and confirmed the importance of selecting the appropriate type of fining agent in order to maintain wine quality.

Influence of activated charcoal amendment to contaminated soil on dieldrin and nutrient uptake by cucumbers

Activated charcoal (AC) amendments have been suggested as a promising, cost-effective method to immobilize organic contaminants in soil. We performed pot experiments over two years with cucumber ( Cucumis sativus L.) grown in agricultural soil with 0.07 mg kg −1 of weathered dieldrin and 0, 200, 400, and 800 mg AC per kg soil. Dieldrin fresh weight concentrations in cucumber fruits were significantly reduced from 0.012 to an average of 0.004 mg kg −1, and total uptake from 2 to 1 μg in the 800 mg kg −1 AC treatment compared to the untreated soil. The treatment effects differed considerably between the two years, due to different meteorological conditions. AC soil treatments did neither affect the availability of nutrients to the cucumber plants nor their yield (total fruit wet weight per pot). Thus, some important prerequisites for the successful application of AC amendments to immobilize organic pollutants in agricultural soils can be considered fulfilled.

Comparison of fractionation techniques to obtain prebiotic galactooligosaccharides

Four different fractionation techniques for obtaining galactooligosaccharides (GOS) free from digestible carbohydrates were compared. Diafiltration did not show any selectivity among mono-, di- and oligosaccharides, whereas yeast treatment to remove monosaccharides allowed a high recovery of GOS and disaccharides. Activated charcoal treatment showed a different selectivity in GOS recovery depending on the concentration of ethanolic water solutions used (1–15%). Ethanolic solutions of 8% led to a high recovery of GOS (∼90%), but 20% of disaccharides were also recovered, whilst solutions with 10% ethanol allowed almost complete removal of disaccharides, but only ∼53% of GOS trisaccharides were recovered. Finally, the purest GOS fractions (degree of polymerization up to 8) were obtained using size exclusion chromatography.

Inhibition of Pichia stipitis fermentation of hydrolysates from olive tree cuttings

The ethanolic fermentation of liquid fractions (hydrolysates) issued from dilute acid pre-treatment of olive tree biomass by Pichia stipitis is reported for the first time. On the one side, P. stipitis has been reported as the most promising naturally occurring C5 fermenting microorganism; on the other side, olive tree biomass is a renewable, low cost, and lacking of alternatives agricultural residue especially abundant in Mediterranean countries. The study was performed in two steps. First, the fermentation performance of P. stipitis was evaluated on a fermentation medium also containing the main inhibitors found in these hydrolysates (acetic acid, formic acid, and furfural), as well as glucose and xylose as carbon sources. The effect of inhibitors, individually or in a mixture, on kinetic and yield parameters was calculated. In a second step, hydrolysates obtained from 1% (w/w) sulfuric acid pre-treatment of olive tree biomass at 190°C for 10 min were used as a real fermentation medium with the same microorganism. Due to inhibition, effective fermentation required dilution of the hydrolysate and either overliming or activated charcoal treatment. Results show that ethanol yields obtained from hydrolysates, ranging from 0.35 to 0.42 g/g, are similar to those from synthetic medium, although the process proceeds at lower rates. Inhibiting compounds affect the fermentation performance in a synergistic way. Furfural is rapidly assimilated by the yeast; acetic acid and formic acid concentrations decrease slowly during the process. Activated charcoal or overliming detoxification improve the fermentability of diluted hydrolysates.

Fractionation of Honey Carbohydrates Using Pressurized Liquid Extraction with Activated Charcoal

This article describes the development of a new procedure that combines the use of activated charcoal and pressurized liquid extraction (PLE) to obtain enriched fractions of di- and trisaccharides from honey. Honey was adsorbed onto activated charcoal and packed into a PLE extraction cell. Optimum results were obtained at 10 MPa and 40 degrees C using two consecutive PLE cycles: first, 1:99 (v/v) ethanol/water for 5 min and second, 50:50 (v/v) ethanol/water for 10 min. Di- and trisaccharide fractions were enriched after PLE treatment, accounting for 73% and 8% of total carbohydrates, respectively. This procedure was also compared with other methodologies reported in the literature for the fractionation of honey carbohydrates (yeast treatment and extraction from activated charcoal). While the removal of monosaccharides was more efficient with yeast treatment, recovery of di- and trisaccharides was higher when either the PLE or the activated charcoal treatment was used. PLE was found to be the faster technique; it also required less solvent volume and minimized handling of the sample.

Flavonoids induce germination of basidiospores of the ectomycorrhizal fungus Suillus bovinus

Under laboratory conditions, spores of ectomycorrhizal fungi usually germinate very poorly or not at all. In a previous study, we showed that spores of the ectomycorrhizal fungus Suillus bovinus germinated through the combination of activated charcoal treatment of media and co-culture with seedlings of Pinus densiflora, which suggested that some substances contained in root exudates induced the germination. Among the compounds reported from root exudates, flavonoids have been elucidated to play various and substantial roles in plant-microbe interactions; we therefore investigated the effects of flavonoids on basidiospore germination of S. bovinus by the diffusion gradient assay on water agar plates pretreated with charcoal powder. Seven out of the 11 flavonoids tested, hesperidin, morin, rutin, quercitrin, naringenin, genistein, and chrysin, had greater effects than controls, whereas flavone, biochanin A, luteolin, and quercetin showed no positive effects. The effective concentration presumably corresponded to several micromolar levels, which was equivalent to those effective for pollen development, nod gene induction, and spore germination of F. solani f. sp. pisi and AM fungi. The results suggest that flavonoids play a role as signaling molecules in symbiotic relationships between woody plants and ectomycorrhizal fungi.

Effects of urine alkalization and activated charcoal on the pharmacokinetics of orally administered carprofen in dogs

To investigate the effects of oral administration of activated charcoal (AC) and urine alkalinization via oral administration of sodium bicarbonate on the pharmacokinetics of orally administered carprofen in dogs. 6 neutered male Beagles. Each dog underwent 3 experiments (6-week interval between experiments). The dogs received a single dose of carprofen (16 mg/kg) orally at the beginning of each experiment; after 30 minutes, sodium bicarbonate (40 mg/kg, PO), AC solution (2.5 g/kg, PO), or no other treatments were administered. Plasma concentrations of unchanged carprofen were determined via high-performance liquid chromatography at intervals until 48 hours after carprofen administration. Data were analyzed by use of a Student paired t test or Wilcoxon matched-pairs rank test. Compared with the control treatment, administration of AC decreased plasma carprofen concentrations (mean +/- SD maximum concentration was 85.9 +/- 11.9 mg/L and 58.1 +/- 17.6 mg/L, and area under the time-concentration curve was 960 +/- 233 mg/L x h and 373 +/- 133 mg/L x h after control and AC treatment, respectively). The elimination half-life remained constant. Administration of sodium bicarbonate had no effect on plasma drug concentrations. After oral administration of carprofen in dogs, administration of AC effectively decreased maximum plasma carprofen concentration, compared with the control treatment, probably by decreasing carprofen absorption. Results suggest that AC can be used to reduce systemic carprofen absorption in dogs receiving an overdose of carprofen. Oral administration of 1 dose of sodium bicarbonate had no apparent impact on carprofen kinetics in dogs.

에틸렌 흡착제와 활성탄 처리에 의한 저장 포도의 품질 특성

In order to ensure a stable supply of grapes for consumers and to extend grape storage, we investigated changes in the quality of grapes (Vitis labruscana) stored after treatment with ethylene-absorbent (EA) or activated charcoal (AC). We treated harvested ‘Sheridan’ and ‘Muscat Bailey A’ grapes with EA and with 0.1, 0.5, 1.0, and 2.0% (w/w) AC, and stored them at 0±1℃, 90±2% humidity for 60 days. After the EA or AC treatment, the storability of the ‘Sheridan’ and ‘Muscat Bailey A’ grapes was increased, as compared with non-treatment, and ‘Sheridan’ kept better than ‘Muscat Bailey A’. The quality of the stored grapes maintained with EA or the amount of AC, which decreased the rate of weight loss, abnormal fruit development, berry abscission, saccharinity, and growth of fungi. The free sugar and anthocyanin contents in the pericarp increased gradually in both ‘Sheridan’ and ‘Muscat Bailey A’, and increased more in ‘Sheridan’. Conversely, the total acidity of ‘Sheridan’ and ‘Muscat Bailey A’ decreased with storage, and decreased less in ‘Sheridan’. There were no differences in the free sugar content, anthocyanin content, and total acidity among treatments. The changes in grape quality with storage were delayed in the order of EA, 2% AC, 1% AC, 0.5% AC, and 0.1% AC. Ultimately, we postulate that EA and 2% AC best maintain the qualities of grape, and extend the grape storage period.

Wastewater treatment in dairy industries — possibility of reuse

The reuse of wastewater from the dairy industry was investigated using coagulation, adsorption and membrane separation. Dairy industry was chosen as it requires huge volume of water. In recent times, development of newer membranes with high flux/rejection characteristics have increased the probability of water reuse and recycling up to a greater extent. In this investigation thorough pretreatment studies were done using different types of coagulants categorized as inorganic, polymeric, and organic having biological origins. The coagulant treatment was performed at various pH using different dosages and it was followed by activated charcoal treatment. The combined effects of these two pretreatment methodologies were evaluated. The color and the odor were removed completely and permanently after charcoal treatment. The pretreated water was passed through a cross flow reverse osmosis membrane system and the permeate water was found to have very good quality. This was compared to the process water used by the dairy farm and was found that the water can be recycled or reused.

Polyhydroxyalkanoate copolymers from forest biomass

The potential for the use of woody biomass in poly-beta-hydroxyalkanoate (PHA) biosynthesis is reviewed. Based on previously cited work indicating incorporation of xylose or levulinic acid (LA) into PHAs by several bacterial strains, we have initiated a study for exploring bioconversion of forest resources to technically relevant copolymers. Initially, PHA was synthesized in shake-flask cultures of Burkholderia cepacia grown on 2.2% (w/v) xylose, periodically amended with varying concentrations of levulinic acid [0.07-0.67% (w/v)]. Yields of poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate) [P(3HB-co-3HV)] from 1.3 to 4.2 g/l were obtained and could be modulated to contain from 1.0 to 61 mol% 3-hydroxyvalerate (3HV), as determined by 1H and 13C NMR analyses. No evidence for either the 3HB or 4HV monomers was found. Characterization of these P(3HB-co-3HV) samples, which ranged in molecular mass (viscometric, Mv) from 511-919 kDa, by differential scanning calorimetry and thermogravimetric analyses (TGA) provided data which were in agreement for previously reported P(3HB-co-3HV) copolymers. For these samples, it was noted that melting temperature (Tm) and glass transition temperature (Tg) decreased as a function of 3HVcontent, with Tm demonstrating a pseudoeutectic profile as a function of mol% 3HV content. In order to extend these findings to the use of hemicellulosic process streams as an inexpensive carbon source, a detoxification procedure involving sequential overliming and activated charcoal treatments was developed. Two such detoxified process hydrolysates (NREL CF: aspen and CESF: maple) were each fermented with appropriate LA supplementation. For the NREL CF hydrolysate-based cultures amended with 0.25-0.5% LA, P(3HB-co-3HV) yields, PHA contents (PHA as percent of dry biomass), and mol% 3HV compositions of 2.0 g/l, 40% (w/w), and 16-52 mol% were obtained, respectively. Similarly, the CESF hydrolysate-based shake-flask cultures yielded 1.6 g/l PHA, 39% (w/w) PHA contents, and 4-67 mol% 3HV compositions. These data are comparable to copolymer yields and cellular contents reported for hexose plus levulinic acid-based shake-flask cultures, as reported using Alcaligenes eutrophus and Pseudomonas putida. However, our findings presage a conceivable alternative, forestry-based biorefinery approach for the production of value-added biodegradable PHA polymers. Specifically, this review describes the current and potential utilization of lignocellulosic process streams as platform precursors to PHA polymers including hemicellulosic hydrolysates, residual cellulose-derived levulinic acid, tall oil fatty acids (Kraft pulping residual), and lignin-derived aromatics.

Poly-3-hydroxybutyrate (P3HB) production by bacteria from xylose, glucose and sugarcane bagasse hydrolysate.

Fifty-five bacterial strains isolated from soil were screened for efficient poly-3-hydroxybutyrate (P3HB) biosynthesis from xylose. Three strains were also evaluated for the utilization of bagasse hydrolysate after different detoxification steps. The results showed that activated charcoal treatment is pivotal to the production of a hydrolysate easy to assimilate. Burkholderia cepacia IPT 048 and B. sacchari IPT 101 were selected for bioreactor studies, in which higher polymer contents and yields from the carbon source were observed with bagasse hydrolysate, compared with the use of analytical grade carbon sources. Polymer contents and yields, respectively, reached 62% and 0.39 g g(-1) with strain IPT 101 and 53% and 0.29 g g(-1) with strain IPT 048. A higher polymer content and yield from the carbon source was observed under P limitation, compared with N limitation, for strain IPT 101. IPT 048 showed similar performances in the presence of either growth-limiting nutrient. In high-cell-density cultures using xylose plus glucose under P limitation, both strains reached about 60 g l(-1) dry biomass, containing 60% P3HB. Polymer productivity and yield from this carbon source reached 0.47 g l(-1) h(-1) and 0.22 g g(-1), respectively.

Effect of Detoxification of Dilute-Acid Corn Fiber Hydrolysate on Xylitol Production

Four different detoxification methods were evaluated for the production of xylitol from corn fiber dilute-acid hydrolysate using Candida tropicalis. Although C. tropicalis could ferment the dilute partially neutralized hydrolysate to xylitol in low yields (0.1 g/g), it could not ferment the concentrated hydrolysate. Overliming, calcium hydroxide neutralization, neutralization combined with activated charcoal, and overliming combined with activated charcoal methods were used to improve the fermentation of the concentrated hydrolysates. The partial neutralization combined with activated charcoal treatment was the most effective method with respect to xylitol yield and productivity. The highest xylitol yield (0.4 g of xylitol/g of xylose) was obtained for the highest concentration of hydrolysate (three times the original) that had been treated with calcium hydroxide and activated charcoal. The corresponding productivity was 0.23 g/(L x h). Overliming caused reduction in xylitol yield.

Comparison of the Zeolite Sodium Chabazite and Activated Charcoal for Ammonia Control in Sealed Containers

Zeolites are often used for water quality control in live fish transport. Activated charcoal has also been proposed for this purpose. In this experiment, the effects of the zeolite sodium chabazite and granular activated charcoal on water quality were studied in nine sealed 500 ml flasks held at 22 o C. Three treatments were commercial grey zeolite (90% pure herschelite-sodium chabazite), commercial granular activated charcoal and control, each in triplicate. To each treatment was added 10 mg·l total ammonia-nitrogen (TAN) and for simulated stress control 9 g·l un-iodized salt (NaCl). Zeolite and activated charcoal were added at the rate of 20 g·l. In 96 h, total ammonia-nitrogen (TAN) means in the zeolite treatment and in the activated charcoal treatment both decreased significantly from 9.59 to 4.02 mg·l, and 9.40 to 7.91 mg·l, respectively. However, the mean pH of the zeolite treatment increased from 7.85 to 7.95, while the mean pH in the activated charcoal treatment increased from 8.12 to 9.13. Calculated un-ionized ammonia (UIA) levels of the zeolite treatment decreased from 0.35 to 0.16 mg·l, after 96 h, although not significantly. In the activated charcoal treatment, UIA increased significantly from 0.50 to 3.02 mg·l. Significant differences were observed in TAN, UIA and pH between the activated charcoal treatment and the zeolite treatment. Zeolite significantly controlled TAN and UIA, with stable pH. Activated charcoal slightly decreased TAN, but greatly increased pH and UIA. Therefore, this kind of activated charcoal reduced water quality and is judged to be not useful in fish transport. Commercial grey zeolite, even with salt addition, was effective in removing toxic ammonia for live fish transport.