据9月份Microbiology杂志上的一篇文章，科学家发现一种微生物能够快速将工业金属废料转变成高价值的催化剂进而用于清洁能源的生产。
据文章报道，伯明翰大学的研究人员发现了一种新机制，其允许土壤中的常见细菌Desulfovibrio desulfuricans重新从工业废料中获得稀有金属钯。
钯是铂族金属（PGMs）中的一种，由于其具有优越的化学性能而得到广泛使用。PGMs一般使用于催化系统中，是自我催化转换器的活性成分，该转换机制能够降低温室气体排放。
Kevin Deplanche博士主持了这项研究，同时他也解释了这种再生PGMs新技术的必要性。他表示，一方面这些金属是稀有资源，这点可以从它们在市场中的高价值体现出来。此外，在过去的10年，这些金属也一直是供少于求。因此研究再生钯的方法对于保证未来这些资源的利用是很重要的，也是很有必要的。
先前的研究表明，Desulfovibrio desulfuricans能够减少工业金属废料中的钯。目前科学家已经识别出了参与该过程的小分子。位于细菌膜表面的氢化酶参与钯的再生。包裹着钯微粒的细菌细胞科学家称之为’BioPd’。
研究人员相信BioPd在清洁能源方面具有巨大的潜力，且BioPd是清理工业污染物质的极好催化剂，比如铬。另外BioPd甚至能够用于产生清洁的电能。研究人员表示，他们的最终目的是开发一种简便的技术将工业废料转化成高价值催化剂以进行绿色能源的生产。
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生物谷推荐原文出处：
Microbiology, DOI: 10.1099/mic.0.036681-0
Involvement of hydrogenases in the formation of highly catalytic Pd(0) nanoparticles by bioreduction of Pd(II) using Escherichia coli mutant strains
Kevin Deplanche1, Isabelle Caldelari2,, Iryna P. Mikheenko1, Frank Sargent2 and Lynne E. Macaskie1
1 Unit of Functional Bionanomaterials, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
2 Division of Molecular and Environmental Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
Escherichia coli produces at least three [NiFe] hydrogenases (Hyd-1, Hyd-2 and Hyd-3). Hyd-1 and Hyd-2 are membrane-bound respiratory isoenzymes with their catalytic subunits exposed to the periplasmic side of the membrane. Hyd-3 is part of the cytoplasmically oriented formate hydrogenlyase complex. In this work the involvement of each of these hydrogenases in Pd(II) reduction under acidic (pH 2.4) conditions was studied. While all three hydrogenases could contribute to Pd(II) reduction, the presence of either periplasmic hydrogenase (Hyd-1 or Hyd-2) was required to observe Pd(II) reduction rates comparable to the parent strain. An E. coli mutant strain genetically deprived of all hydrogenase activity showed negligible Pd(II) reduction. Electron microscopy suggested that the location of the resulting Pd(0) deposits was as expected from the subcellular localization of the particular hydrogenase involved in the reduction process. Membrane separation experiments established that Pd(II) reductase activity is membrane-bound and that hydrogenases are required to initiate Pd(II) reduction. The catalytic activity of the resulting Pd(0) nanoparticles in the reduction of Cr(VI) to Cr(III) varied according to the E. coli mutant strain used for the initial bioreduction of Pd(II). Optimum Cr(VI) reduction, comparable to that observed with a commercial Pd catalyst, was observed when the bio-Pd(0) catalytic particles were prepared from a strain containing an active Hyd-1. The results are discussed in the context of economic production of novel nanometallic catalysts.
