Improved Quantification of MicroPET/CT Imaging Using CT-derived Scaling Factors.

Purpose: Combined micro-PET/CT scanners are widely employed to investigate models of brain disorders in rodents using PET-based coregistration. We examined if CT-based coregistration could improve estimates of brain dimensions and consequently estimates of nondisplaceable binding potential (BPND) in rodent PET studies. Procedures: PET and CT scans were acquired on 5 female and 5 male CD-1 mice with PET and CT scans were acquired on 5 female and 5 male CD-1 mice with 3-[18F]fluoro-5-(2-pyridinylethynyl)benzonitrile ([18F]FPEB), a radiotracer for the metabotropic glutamate receptor subtype 5 (mGluR5). In the proposed PET/CT (PTCT) approach, the tracer-specific standard volume was dimension-customized to each animal using the scaling factors from CT-to-standard CT coregistration to simplify PET-to-standard PET coregistration (i.e., 3 CT- and 6 PET-derived parameters). For comparison, conventional PET-based coregistration was performed with 9 (PT9) or 12 (PT12) parameters. PET frames were transferred to the standard space by the three approaches (PTCT, PT9, and PT12) to obtain regional time-activity curves (TACs) and BPND in 14 standard volumes of interest (VOIs). Lastly, CT images of the animals were transferred to the standard space by CT-based parameters from PTCT and with the scaling factors replaced with those from PET-based PT9 to evaluate agreement of the skull to the standard CT. Results: The PET-based approaches showed various degrees of underestimations of scaling factors in the posterior-anterior-direction compared to PTCT, which resulted in negatively proportional overestimation of radioactivity in the cerebellum (reference region) up to 20%, and proportional, more prominent underestimation of BPND in target regions down to -50%. The skulls of individual animals agreed with the standard skull for scaling factors from PTCT but not for the scaling factors from PT9, which suggested inaccuracy of the latter. Conclusions: The results indicated that conventional PET-based coregistration approaches could yield biased estimates of BPND due to erroneous estimates of brain dimensions when applied to tracers for which the cerebellum serves as reference region. The proposed PTCT provides evidence of a quantitative improvement over PET-based approaches for brain studies using micro-PET/CT scanners.

Fragile X Mental Retardation Protein and Cerebral Expression of Metabotropic Glutamate Receptor Subtype 5 in Men with Fragile X Syndrome: A Pilot Study.

Multiple lines of evidence suggest that a deficiency of Fragile X Mental Retardation Protein (FMRP) mediates dysfunction of the metabotropic glutamate receptor subtype 5 (mGluR5) in the pathogenesis of fragile X syndrome (FXS), the most commonly known single-gene cause of inherited intellectual disability (ID) and autism spectrum disorder (ASD). Nevertheless, animal and human studies regarding the link between FMRP and mGluR5 expression provide inconsistent or conflicting findings about the nature of those relationships. Since multiple clinical trials of glutamatergic agents in humans with FXS did not demonstrate the amelioration of the behavioral phenotype observed in animal models of FXS, we sought measure if mGluR5 expression is increased in men with FXS to form the basis for improved clinical trials. Unexpectedly marked reductions in mGluR5 expression were observed in cortical and subcortical regions in men with FXS. Reduced mGluR5 expression throughout the living brains of men with FXS provides a clue to examine FMRP and mGluR5 expression in FXS. In order to develop the findings of our previous study and to strengthen the objective tools for future clinical trials of glutamatergic agents in FXS, we sought to assess the possible value of measuring both FMRP levels and mGluR5 expression in men with FXS. We aimed to show the value of measurement of FMRP levels and mGluR5 expression for the diagnosis and treatment of individuals with FXS and related conditions. We administered 3-[18F]fluoro-5-(2-pyridinylethynyl)benzonitrile ([18F]FPEB), a specific mGluR5 radioligand for quantitative measurements of the density and the distribution of mGluR5s, to six men with the full mutation (FM) of FXS and to one man with allele size mosaicism for FXS (FXS-M). Utilizing the seven cortical and subcortical regions affected in neurodegenerative disorders as indicator variables, adjusted linear regression of mGluR5 expression and FMRP showed that mGluR5 expression was significantly reduced in the occipital cortex and the thalamus relative to baseline (anterior cingulate cortex) if FMRP levels are held constant (F(7,47) = 6.84, p < 0.001).These findings indicate the usefulness of cerebral mGluR5 expression measured by PET with [18F]FPEB and FMRP values in men with FXS and related conditions for assessments in community facilities within a hundred-mile radius of a production center with a cyclotron. These initial results of this pilot study advance our previous study regarding the measurement of mGluR5 expression by combining both FMRP levels and mGluR5 expression as tools for meaningful clinical trials of glutamatergic agents for men with FXS. We confirm the feasibility of this protocol as a valuable tool to measure FMRP levels and mGluR5 expression in clinical trials of individuals with FXS and related conditions and to provide the foundations to apply precision medicine to tailor treatment plans to the specific needs of individuals with FXS and related conditions.

Reduced Expression of Cerebral Metabotropic Glutamate Receptor Subtype 5 in Men with Fragile X Syndrome.

Glutamatergic receptor expression is mostly unknown in adults with fragile X syndrome (FXS). Favorable behavioral effects of negative allosteric modulators (NAMs) of the metabotropic glutamate receptor subtype 5 (mGluR5) in fmr1 knockout (KO) mouse models have not been confirmed in humans with FXS. Measurement of cerebral mGluR5 expression in humans with FXS exposed to NAMs might help in that effort. We used positron emission tomography (PET) to measure the mGluR5 density as a proxy of mGluR5 expression in cortical and subcortical brain regions to confirm target engagement of NAMs for mGluR5s. The density and the distribution of mGluR5 were measured in two independent samples of men with FXS (N = 9) and typical development (TD) (N = 8). We showed the feasibility of this complex study including MRI and PET, meaning that this challenging protocol can be accomplished in men with FXS with an adequate preparation. Analysis of variance of estimated mGluR5 expression showed that mGluR5 expression was significantly reduced in cortical and subcortical regions of men with FXS in contrast to age-matched men with TD.

Dataset of quantitative structured office measurements of movements in the extremities.

A low-cost quantitative structured office measurement of movements in the extremities of people with Parkinson's disease [1,2] was performed on people with Parkinson's disease, multiple system atrophy, and age-matched healthy volunteers. Participants underwent twelve videotaped procedures rated by a trained examiner while connected to four accelerometers [1,2] generating a trace of the three location dimensions expressed as spreadsheets [3,4]. The signals of the five repetitive motion items [1,2] underwent processing to fast Fourier [5] and continuous wavelet transforms [6]. The dataset [7] includes the coding form with scores of the live ratings [1,2], the raw files [3], the converted spreadsheets [4], and the fast Fourier [5] and continuous wavelet transforms [6]. All files are unfiltered. The data also provide findings suitable to compare and contrast with data obtained by investigators applying the same procedure to other populations. Since this is an inexpensive procedure to quantitatively measure motions in Parkinson's disease and other movement disorders, this will be a valuable resource to colleagues, particularly in underdeveloped regions with limited budgets. The dataset will serve as a template for other investigations to develop novel techniques to facilitate the diagnosis, monitoring, and treatment of Parkinson's disease, other movement disorders, and other nervous and mental conditions. The procedure will provide the basis to obtain objective quantitative measurements of participants in clinical trials of new agents.

Evaluation of 18F-RO-948 PET for Quantitative Assessment of Tau Accumulation in the Human Brain.

The availability of tau PET radioligands enables quantitative assessment of tau density and distribution in the human brain. We evaluated the kinetics of a novel radioligand, 18F-RO-948 (previously referred to as 18F-RO6958948), and its ability to identify tau positivity in individual patients with mild Alzheimer disease (AD). Methods: Eleven subjects with amyloid-positive mild AD, 5 amyloid-negative older control subjects (OC), and 5 younger control subjects (YC) completed 1 or 2 (4 AD and 5 OC) PET scans with 18F-RO-948 for 90, 120, or 200 min. The kinetics of the radioligand was evaluated with standard compartmental and noncompartmental models (with plasma data in 70% of cases), tissue-reference methods, and SUV ratio. These approaches were applied to assess the ability of 18F-RO-948 to discriminate AD subjects from OC subjects. Results: The plasma reference graphical analysis appeared to be the optimal method of quantification for 18F-RO-948, yielding strictly time-consistent values of distribution volume and distribution volume ratio at 90 min against the analyses at 120 and 200 min. The reference tissue graphical analysis and SUV ratio were cross-validated against plasma reference graphical analysis. Test-retest evaluation showed excellent reproducibility. A proposed novel index of tau load, the regional tau-positive fraction, showed high values in the medial and lateral temporal and parietal regions in AD and successfully separated AD subjects from OC and YC subjects with a significant margin. Conclusion:18F-RO-948 appears to be a promising radioligand for quantitative imaging of tau in the brain of AD patients.

Characterization of 3 Novel Tau Radiopharmaceuticals, 11C-RO-963, 11C-RO-643, and 18F-RO-948, in Healthy Controls and in Alzheimer Subjects.

11C-RO-963, 11C-RO-643, and 18F-RO-948 (previously referred to as 11C-RO6924963, 11C-RO6931643, and 18F-RO6958948, respectively) have been reported as promising PET tracers for tau imaging based on in vitro and preclinical PET data. Here we describe the first, to our knowledge, human evaluation of these novel radiotracers. Methods: Amyloid PET-positive Alzheimer disease (AD) subjects and younger controls each received 2 different tau tracers. Dynamic 90-min scans were obtained after bolus injection of 11C-RO-963, 11C-RO-643, or 18F-RO-948. Arterial blood sampling was performed on 11 healthy controls and 11 AD subjects. Regions were defined on MR images, and PET data were quantified by plasma reference graphical analysis (for total distribution volume) and target cerebellum ratio (SUV ratios of 60- to 90-min frames). SUV ratio images were also analyzed voxelwise. Five older controls each underwent 2 scans with 18F-RO-948 for evaluation of test-retest variability. Four AD subjects underwent a repeated 18F-RO-948 scan 6-22 mo after the first scan. Six additional healthy controls (3 men and 3 women; age range, 41-67 y) each underwent 1 whole-body dosimetry scan with 18F-RO-948. Results: In younger controls, SUVpeak was observed in the temporal lobe with values of approximately 3.0 for 11C-RO-963, 1.5 for 11C-RO-643, and 3.5 for 18F-RO-948. Over all brain regions and subjects, the trend was for 18F-RO-948 to have the highest SUVpeak, followed by 11C-RO-963 and then 11C-RO-643. Regional analysis of SUV ratio and total distribution volume for 11C-RO-643 and 18F-RO-948 clearly discriminated the AD group from the healthy control groups. Compartmental modeling confirmed that 11C-RO-643 had lower brain entry than either 11C-RO-963 or 18F-RO-948 and that 18F-RO-948 showed better contrast between (predicted) areas of high versus low tau accumulation. Thus, our subsequent analysis focused on 18F-RO-948. Both voxelwise and region-based analysis of 18F-RO-948 binding in healthy controls versus AD subjects revealed multiple areas where AD subjects significantly differed from healthy controls. Of 22 high-binding regions, 13 showed a significant group difference (after ANOVA, F(1,21) = 45, P < 10-5). Voxelwise analysis also revealed a set of symmetric clusters where AD subjects had higher binding than healthy controls (threshold of P < 0.001, cluster size > 50). Conclusion:18F-RO-948 demonstrates characteristics superior to 11C-RO-643 and 11C-RO-963 for characterization of tau pathology in AD. Regional binding data and kinetic properties of 18F-RO-948 compare favorably with other existing tau PET tracers.

Metabotropic glutamate receptor 5 tracer [18F]-FPEB displays increased binding potential in postcentral gyrus and cerebellum of male individuals with autism: a pilot PET study.

BACKGROUND: Autism is a neurodevelopmental disorder that is first manifested during early childhood. Postmortem experiments have identified significantly elevated expression of metabotropic glutamate receptor 5 (mGluR5) in cerebellar vermis and prefrontal cortex of individuals with autism. METHODS: In the current study we employed the mGluR5 tracer [18F]-3-fluoro-5-[(pyridin-3-yl)ethynyl]benzonitrile ([18F]-FPEB) to quantify mGluR5 binding in vivo in adults with autism vs. healthy controls using positron emission tomography (PET). RESULTS: We identified significantly higher [18F]-FPEB binding potential in the postcentral gyrus and cerebellum of individuals with autism. There was a significant negative correlation between age and [18F]-FPEB binding potential in the cerebellum but not in the postcentral gyrus. In the precuneus, [18F]-FPEB binding potential correlated positively with the lethargy subscale score for the Aberrant Behavioral Checklist (ABC). In cerebellum, there were significant negative correlations between [18F]-FPEB binding potential and ABC total score, ABC hyperactivity subscale score, and the ABC inappropriate speech subscale score. CONCLUSIONS: These novel findings demonstrate for the first time that mGluR5 binding is altered in critical brain areas of subjects with autism, suggesting abnormal glutamate signaling in these regions. Finally, the correlations between altered [18F]-FPEB binding potential in the cerebellum and precuneus suggest that some autistic symptoms may be influenced by abnormal glutamate signaling.

Objectively Measured Sleep and ß-amyloid Burden in Older Adults: A Pilot Study.

BACKGROUND/AIMS: Although disturbed sleep is associated with cognitive deficits, the association between sleep disturbance and Alzheimer's disease (AD) pathology is unclear. In this pilot study, we examined the extent to which sleep duration, sleep quality, and sleep-disordered breathing (SDB) are associated with ß-amyloid (Aß) deposition in the brains of living humans. METHODS: We studied 13 older adults (8 with normal cognition and 5 with mild cognitive impairment (MCI)). Participants completed neuropsychological testing, polysomnography and Aß imaging with [11C]-Pittsburgh compound B. RESULTS: Among participants with MCI, higher apnea-hypopnea index and oxygen desaturation index were associated with greater Aß deposition, globally and regionally in the precuneus. There were no significant associations between SDB and Aß deposition among cognitively normal participants. There were no significant associations between sleep duration or sleep fragmentation and Aß deposition. CONCLUSION: These preliminary results suggest that, among older adults with MCI, greater SDB severity is associated with greater Aß deposition.

Biological treatment and modeling aspect of BTEX abatement process in a biofilter.

In the present work, a laboratory scale corn-cob based biofilter inoculated with Bacillus sphaericus (MTCC 8103) was used for degradation of BTEX for a period of 86 days. The overall performance of a biofilter evaluated in terms of its elimination capacity by using 3-D mesh technique. Maximum removal efficiency was found more than 96.43% for all four compounds in each phase of experiments. A maximum elimination capacity (EC) of 60.89 gm(-3)h(-1) of the biofilter was obtained at inlet BTEX load of 63.14 gm(-3)h(-1). The follow-up of carbon dioxide concentration profile through the biofilter revealed that the mass ratio of carbon dioxide produced to the BTEX removed was approximately 2.2, which confirms complete degradation of BTEX. Moreover, BTEX concentration profile along the biofilter depth bed also determined by convection-diffusion reactor (CDR) model.

PET imaging of high-affinity α4ß2 nicotinic acetylcholine receptors in humans with 18F-AZAN, a radioligand with optimal brain kinetics.

UNLABELLED: We evaluated (-)-2-(6-[(18)F]fluoro-2,3'-bipyridin-5'-yl)-7-methyl-7-aza-bicyclo[2.2.1]heptane ((18)F-AZAN), a novel radiotracer that binds to α4ß2 nicotinic acetylcholine receptors (α4ß2-nAChRs) and shows high specific binding and rapid and reversible kinetics in the baboon and human brain. METHODS: We tested safety tolerability and test-retest reliability (n = 5) and proposed initial quantification of (18)F-AZAN receptors in 3 healthy human subjects who had nicotine exposure and 9 who did not. We also present a receptor blocking study in a nicotine subject dosed with the α4ß2-nAChR-selective partial agonist varenicline. RESULTS: Radiation dosimetry PET/CT experiments indicated that most human organs received doses between 0.008 and 0.015 mSv/MBq, with an effective dose of approximately 0.014 mSv/MBq. The tracer rapidly entered the brain, and the peak was reached before 20 min, even for thalamus. Ninety-minute scans were sufficient for (18)F-AZAN to obtain the ratio at equilibrium of specifically bound radioligand to nondisplaceable radioligand in tissue (BPND) using plasma reference graphical analysis, which showed excellent reproducibility of BPND (test-retest variability < 10%) in the nAChR-rich brain regions. Regional plasma reference graphical analysis BP(ND) values exceeded 2 in the midbrain tegmental nuclei, lateral geniculate body, and thalamus for nonsmokers (n = 9) but were less than 1 in the nAChR-poor brain regions. There was a dramatic reduction of (18)F-AZAN brain uptake in smokers and varenicline-treated subjects. CONCLUSION: (18)F-AZAN is a highly specific, safe, and effective PET radioligand for human subjects that requires only 90 min of PET scanning to estimate high-affinity α4ß2-nAChR in the living human brain.

Performance evaluation and model analysis of BTEX contaminated air in corn-cob biofilter system.

Biofiltration of BTEX with corn-cob packing material have been performed for a period of 68 days in five distinct phases. The overall performance of a biofilter has been evaluated in terms of its elimination capacity by using 3-D mesh techniques. Maximum removal efficiency was found more than 99.85% of all four compounds at an EBRT of 3.06 min in phase I for an inlet BTEX concentration of 0.0970, 0.0978, 0.0971 and 0.0968 g m(-3), respectively. Nearly 100% removal achieved at average BTEX loadings of 20.257 g m(-3) h(-1) to biofilter. A maximum elimination capacity (EC) of 20.239 g m(-3) h(-1) of the biofilter was obtained at inlet BTEX load of 20.391 g m(-3) h(-1). Moreover, using convection-diffusion reaction (CDR) model for biofilter depth shows good agreement with the experimental values for benzene, toluene and ethyl benzene, but for o-xylene the model results deviated from the experimental.

Modelling and computational fluid dynamic behaviour of a biofilter treating benzene.

Biofiltration of an air stream containing benzene has been studied in a laboratory biofilter packed with a mixture of compost, sugar cane bagasse and GAC. In this study, the overall performance of a biofilter has been evaluated in terms of its elimination capacity by using 3-D mesh techniques. The overall results indicate that the agreement between experimental data and estimated model predictions is excellent for benzene. The benzene concentration profiles along the depth of biofilter have also been determined using a convection-diffusion reactor (CDR) model and computational fluid dynamic (CFD) technique. At low flow rates and low concentrations of benzene, the concentration profile throughout the biofilter shows good agreement with CDR model and it becomes more curved and resembles typical decay. Combined analysis of experimental results with CDR model and the CFD shows that the profile of benzene at low concentration becomes more curved and then linear at high concentration. The benzene profiles obtained by CFD are within 5% accuracy of experimental results. The CDR and CFD models are found to be able to predict concentration profiles preciously with depth under the experimental conditions.

Biodegradation of mono-chlorobenzene by using a trickle bed air biofilter (TBAB).

In the present study, performance of the trickle bed airbiofilter (TBAB) for treating mono-chlorobenzene (MCB) was evaluated for various influent volatile organic compound (VOC) loadings using coal and mixed consortium of activated sludge as the packing material. Microbial acclimation to MCB was achieved by exposing the system continuously for 31 d to an average inlet MCB concentration of 0.688 g m(-3) at an empty bed residence time (EBRT) of 188 s. The TBAB achieved maximum removal efficiency of 87% at an EBRT of 188 s for an inlet concentration of 0.681 g m(-3), which is quite significance than the values reported in the literature. Elimination capacities of MCB increased with an increase of the influent VOC loading, but an opposite trend was observed for the removal efficiency The maximum elimination capacity of the biofilter was 110.75 g m(-3) hr(-1) at an inlet MCB concentration of 1.47 g m(-3). The effect of starvation on the TBAB was also studied. After starvation, the TBAB lost its ability to degrade MCB initially However the biofilter recovered very quickly Evaluation of the concentration profile along the bed height indicated that the bottom section of TBAB has the best performance for all concentrations. By using Wani's method of macrokinetic determination based on simple Monod kinetics, the maximum removal rate of MCB, r(max) and saturation constant K(m) was to be found as 1.304 g m(-3)s(-1) and 113.446 g m(-3), respectively.

Biodegradation of pyridine by the new bacterial isolates S. putrefaciens and B. sphaericus.

In this study, two bacterial strains capable of utilizing pyridine as a sole carbon source were isolated from biofilters. Based on the biochemical test, the organisms were identified as Shewanella putrefaciens and Bacillus sphaericus. In liquid cultures, S. putrefaciens and B. sphaericus degraded pyridine quite effectively up to 500 mg L(-1). S. putrefaciens degrades 500 mg L(-1) of pyridine completely within 140 h, whereas the B. sphaericus degrades 500 mg L(-1) of pyridine only nearly 75% and takes a longer duration of 150 h. S. putrefaciens used pyridine as sole carbon and energy source better than B. sphaericus. Monod's and Haldane's inhibitory growth models were used to obtain maximum specific growth rate (micro(max)), half saturation (K(s)) and substrate inhibition (K(i)) constant for pyridine by using S. putrefaciens and B. sphaericus. The high value of K(i) for S. putrefaciens than B. sphaericus indicates that the inhibition effect can be observed only in a high concentration range. The S. putrefaciens degrades pyridine with a faster rate than B. sphaericus. S. putrefaciens can be used effectively for the treatment of pyridine bearing wastewater and as an inoculum in a biofilter treating pyridine-laden gas.

Biofiltration and kinetic aspects of a biotrickling filter for the removal of paint solvent mixture laden air stream.

In the present study, removal of methyl ethyl ketone (MEK), toluene, n-butyl acetate and o-xylene (MTBX) emitted from the paint industry was carried out in a coal based biotrickling filter. When the influent MTBX loadings were less than 120 gm(-3)h(-1), nearly 100% removal could be achieved. A maximum elimination capacity of 184.86 gm(-3)h(-1) was obtained at a MTBX load of 278.27 gm(-3)h(-1) with an empty bed residence time of 42.4s in phase V. Results showed that the condition was the most favorable for n-butyl acetate degradation followed by MEK, toluene and then o-xylene. The corresponding maximum removal rate, r(max) values of MTBX were calculated as 0.085, 0.033, 0.16 and 0.024 gm(-3)h(-1), respectively. Standard deviation of error in prediction of MEK, toluene and o-xylene removal were within limit of 10%, while in the case of n-butyl acetate this was approximately 60%. The MTBX concentration profiles along the depth were also determined by using convection-diffusion reaction (CDR) model. It was observed that at low concentration and low flow rate, the model is in good agreement with the experimental values for MEK, toluene and n-butyl acetate, but for o-xylene the model results deviated from the experimental.

Combined removal of BTEX in air stream by using mixture of sugar cane bagasse, compost and GAC as biofilter media.

Biofiltration of air stream containing mixture of benzene, toluene, ethyl benzene and o-xylene (BTEX) has been studied in a lab-scale biofilter packed with a mixture of compost, sugar cane bagasse and granulated activated carbon (GAC) in the ratio 55:30:15 by weight. Microbial acclimation was achieved in 30 days by exposing the system to average BTEX inlet concentration of 0.4194 gm(-3) at an empty bed residence time (EBRT) of 2.3 min. Biofilter achieved maximum removal efficiency more than 99% of all four compounds for throughout its operation at an EBRT of 2.3 min for an inlet concentration of 0.681 gm(-3), which is quite significance than the values reported in the literature. The results indicate that when the influent BTEX loadings were less than 68 gm(-3)h(-1) in the biofilter, nearly 100% removal could be achieved. A maximum elimination capacity (EC) of 83.65 gm(-3)h(-1) of the biofilter was obtained at inlet BTEX load of 126.5 gm(-3)h(-1) in phase IV. Elimination capacities of BTEX increased with the increase in influent VOC loading, but an opposite trend was observed for the removal efficiency. The production of CO(2) in each phase (gm(-3)h(-1)) was also observed at steady state (i.e. at maximum removal efficiency). Moreover, the high concentrations of nitrogen in the nutrient solution may adversely affect the microbial activity possibly due to the presence of high salt concentrations. Furthermore, an attempt was also made to isolate the most profusely grown BTEX-degrading strain. A Gram-positive strain had a high BTEX-degrading activity and was identified as Bacillus sphaericus by taxonomical analysis, biochemical tests and 16S rDNA gene analysis methods.

Kinetics of the removal of mono-chlorobenzene vapour from waste gases using a trickle bed air biofilter.

The performance of a trickle bed air biofilter (TBAB) in the removal of mono-chlorobenzene (MCB) was evaluated in concentrations varying from 0.133 to 7.187 g m(-3) and at empty bed residence time (EBRT) varying from 37.7 to 188.52 s. More than 90% removal efficiency in the trickle bed air biofilter was achieved for the inlet MCB concentration up to 1.069 g m(-3) and EBRT less than 94.26 s. The trickle bed air biofilter was constructed with coal packing material, inoculated with a mixed consortium of activated sludge obtained from sewage treatment plant. The continuous performance of the removal of MCB in the trickle bed air biofilter was monitored for various gas concentrations, gas flow rates, and empty bed residence time. The experiment was conducted for a period of 75 days. The trickle bed air biofilter degrading MCB with an average elimination capacity of 80 g m(-3) h(-1) was obtained. The effect of starvation was also studied. After starvation period of 8 days, the degradation was low but recovered within a short period of time. Using macrokinetic determination method, the Michaelis-Menten kinetic constant K(m) and maximum reaction rate, r(max) evaluated as 0.121 g m(-3) s(-1) and 7.45 g m(-3), respectively.