S54 Special Abstracts / Journal of Biotechnology 150S (2010) S1–S576

al., 2009), CH4 and artificial mash gas were used to domesticate themixed methanotrophic cultures capable of stably and effectivelyabating CH4, respectively. Denaturing gradient gel electrophoresis(DGGE) was adopted to analyze the changes of microbial commu-nity structure during the enrichment process. Biofilters and theon site removal of methane from coal bed by using the enrichedmethanotrophic consortia were studied.

Clone library and DGGE showed significant changes in micro-bial communities during the enrichment processes with differentgases. By using the stably enriched methanotrophic consortium, thehigh cell density culture was achieved and the removal efficiencyof CH4 by the biofilter and spraying the consortium in the simu-lated coal bed reached more than 90%. This study demonstratedthat the methanotrophic consortium enriched from the coal minesoils could be effective for reduction of methane control in coalmines.

Acknowledgment: This work was supported by 863 Project ofMOST of China (No. 2006AA02Z203) and the National Key BasicResearch Program (973 plan) (No. 2007CB109203).

Reference

Han, B., et al., 2009. FEMS Microbiology Ecology 70, 196–207.

doi:10.1016/j.jbiotec.2010.08.142

[E.47]

Bio-generated metal-binding polysaccharide as catalyst for syn-thetic applications and organic pollutant transformations

Franco Baldi 1,∗, Davide Marchetto 1, Stefano Paganelli 1, OrestePiccolo 2

1 Cà Foscari University, Italy2 SCSOP, ItalyKeywords: Metal; Exopolysaccharide; Organic compunds; Trans-formation

Bio-generated metal-binding polysaccharides may be novelpotential sustainable catalysts for numerous synthetic applicationsand environment remediation. Depending on the nature of themetal bound to carbohydrates it is possible to perform hydrogena-tion, oxidation and C-C bond formation reactions. In this contextwe are currently investigating the properties of different metals,such as Fe(III) and Pd (II), bound to exopolysaccharides (EPS) pro-duced by a Klebsiella oxytoca BAS-10 isolated from pyrite minesin the Southern Tuscany (Italy). This strain, under anaerobic con-ditions, during Fe(III)-citrate fermentation produces in the latestationary phase a large amount of colloidal material. EPS produc-tion was approximately 6.65 g.l−1 and contains 36% of total ironbound to polysaccharide. EPS can be also prepared without Fe(III)using sodium citrate during the fermentation; by adding an aque-ous or organic solution of some suitable metal salts, it is possible toproduce Me-EPS by cation exchange. Gel or semi-crystalline prod-ucts may be easily recovered and characterized. An eptameric unitwith 4 �-rhamnose, 2 �-glucuronic acids and 1 � − galactose isrepeated to form long polysaccharide molecules of several millionDalton; metals should be located mostly in the proximity of the twoglucuronic acids molecules.

In some experiment tests Fe(III)-EPS catalyzed the oxidationof phenol with 35% H2O2 in water or in a mixture of acetoni-trile/water nearly 1/1 in the presence or absence of catalyticamount of acetic acid, to afford a mixture of catechol and hydro-quinone. In the best reaction conditions, using phenol/H2O2 in1.6–2.6 molar ratio, a conversion of 25–18% of phenol wasobserved with a selectivity ranged 94–96% in dihydroxylated

products (cathecol/hydroquinone molar ratio was nearly 2). Theselectivity based on H2O2, i.e. mol of dihydroxylated derivativesproduced × 100/mol of used hydrogen peroxide. was satisfactoryand equal to 48-58%.

Pd(II)-EPS was also prepared and its application as potentialcatalyst in reductive dehalogenation of halo arenes in a bi-phasewater/organic solvent mixture and in a Heck-type reaction betweenbromo-benzene and unsaturated esters in DMA is currently underinvestigation.

This new approach for preparation and application of cata-lysts seems to be promising with some economic and environmentfriendly advantages and the number of potential application mightbe broad.

doi:10.1016/j.jbiotec.2010.08.143

[E.48]

Purification and function analysis of a broad-spectrumorganomercurial lyase (MerB3) from mercury resistance trans-poson, TnMERI1

Mei-Fang Chien 1,∗, Hui-Tzu Lin 2, Kuo-Hsing Lin 2, Ginro Endo 1,Chieh-Chen Huang 2

1 Faculty of Engineering, Tohoku Gakuin University, Japan2 Department of Life Sciences, National Chung Hsing University, Tai-wanKeywords: Organomercurial compound; Organomercurial lyase;MerB

Organomercurial compounds are potent toxins because of theirlipophilicity and affinity for thiol residues of proteins and tend tobioaccumulate in the ecosystem through the food chain. The most-studied microbial mercury resistance mechanism is an enzymaticsystem which degrades organomercurials to the less toxic elemen-tal mercury. The crucial step is the protonolysis of carbon-mercurybonds by the organomercurial lyase, MerB. However, MerBs identi-fied so far show low similarity and different substrate specificities.In mercury resistant bacterium, Bacillus megaterium MB1, threemerB genes are identified in a transposon, TnMERI1, while MerB3protein confers broad substrate specificity and the fastest removalactivity to p-chloromercuribenzoate. In this study, fast perfor-mance liquid chromatography was applied to purify the MerB3of B. megaterium MB1, and subsequent function analysis was per-formed. The results show that MerB3 catalyzes the protonolysisof the carbon–mercury bonds of both alkyl- and aryl-mercurialsand show that MerB3 performs broader substrate specificity thanMerB2 does. The existence of thiol groups enhances the detoxifica-tion reaction of MerB3, suggesting that the thiol group of MerB3facilitate the cleavage of carbon-mercury bonds. As the resultsof enzyme kinetics parameters, the Km of MerB3 to phenylmer-cury acetate and p-chloromercuribenzoate are 4.5 × 10−3 mM and7.5 × 10−3 mM, respectively, which both of them are much smallerthan the Km of Gram negative MerB. It suggests that the affinity ofB. megaterium MB1 MerB3 is better than Gram negative MerB is.These results show the MerB3 is an appropriate candidate whenapply it to the bioremediation of organomercurial contamination.

doi:10.1016/j.jbiotec.2010.08.144