Real-Time Solvent Tolerance Analysis of Pseudomonas sp Strain LB120ΔC Catalytic Biofilms
Real-Time Solvent Tolerance Analysis of Pseudomonas sp Strain LB120ΔC Catalytic Biofilms
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DOI：
10.1128/aem.02498-10
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发表时间：
2011-03-01
影响因子：
4.4
通讯作者：
Buehler, Katja
中科院分区：
文献类型：
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作者：
Halan, Babu;Schmid, Andreas;Buehler, Katja
生物膜是普遍存在于细胞外聚合物（EPS）基质中的表面相关微生物群落，这使得生物膜具有结构完整性和强度。据报道，生物膜培养的细胞对不利的环境胁迫条件表现出更强的耐受性，因此近年来生物膜用于生物技术应用的兴趣越来越大。我们提出了一种时间和位点分辨、无创、定量的方法来研究生物膜的发育及其对有毒溶剂苯乙烯的反应。假单胞菌属菌株VLB120 Delta C-BT-gfp1在改良的流动电池反应器中生长，并暴露于溶剂苯乙烯中。生物膜培养的细胞表现出稳定的催化活性，在实验期间连续产生(S)-苯乙烯氧化物。生物膜的柱状结构和生长速率不受溶剂存在的影响。然而，在苯乙烯处理过程中，细胞经历了严重的膜损伤，尽管它们明显能够适应溶剂，因为渗透细胞的数量在48小时内从75%到80%下降到40%。同时，ConA蛋白A （ConA）染色的EPS的比例增加，证实了这些多糖在结构完整性和增强生物膜对有毒环境的耐受性方面发挥重要作用的假设。与浮游培养细胞的对照实验相比，假单胞菌生物膜对有毒浓度的苯乙烯的适应性要好得多，因为近65%的生物膜细胞没有渗透（存活），而在类似的浮游培养中只有7%。这些发现强调了生物膜在应激条件下的稳健性及其在精细化学合成方面的潜力。
Biofilms are ubiquitous surface-associated microbial communities embedded in an extracellular polymeric (EPS) matrix, which gives the biofilm structural integrity and strength. It is often reported that biofilm-grown cells exhibit enhanced tolerance toward adverse environmental stress conditions, and thus there has been a growing interest in recent years to use biofilms for biotechnological applications. We present a time-and locus-resolved, noninvasive, quantitative approach to study biofilm development and its response to the toxic solvent styrene. Pseudomonas sp. strain VLB120 Delta C-BT-gfp1 was grown in modified flow-cell reactors and exposed to the solvent styrene. Biofilm-grown cells displayed stable catalytic activity, producing (S)-styrene oxide continuously during the experimental period. The pillar-like structure and growth rate of the biofilm was not influenced by the presence of the solvent. However, the cells experience severe membrane damage during styrene treatment, although they obviously are able to adapt to the solvent, as the amount of permeabilized cells decreased from 75 to 80% down to 40% in 48 h. Concomitantly, the fraction of concanavalin A (ConA)-stainable EPS increased, substantiating the assumption that those polysaccharides play a major role in structural integrity and enhanced biofilm tolerance toward toxic environments. Compared to control experiments with planktonic grown cells, the Pseudomonas biofilm adapted much better to toxic concentrations of styrene, as nearly 65% of biofilm cells were not permeabilized (viable), compared to only 7% in analogous planktonic cultures. These findings underline the robustness of biofilms under stress conditions and its potential for fine chemical syntheses.