石油基塑料的微生物降解

石油基塑料种类繁多、数量巨大、应用广泛,常见的有聚乙烯(PE)、聚丙烯(PP)、聚苯乙烯(PS)、聚氯乙烯(PVC)、聚对苯二甲酸乙二醇酯(PET)、聚氨酯(PUR)等。这些合成塑料因其高分子量、高疏水性及高化学键能的特点难以被微生物降解,从而在环境中长期存在和累积,"白色污染"已经成为一个全球性问题。因此安全经济的微生物降解合成塑料是人类面临的一个选择和难题。文中从微生物资源及相关酶学研究方面综述了聚苯乙烯、聚乙烯、聚丙烯、聚氨酯、聚对苯二甲酸乙二醇酯和聚氯乙烯这6种石油基塑料的生物降解的研究现状。目前关于上述6种石油基塑料的微生物降解研究依然大多停留在微生物资源的寻找中,已发现的具备相关能力的菌株种类较少,并且微生物降解效率均非常缓慢;对于其降解机理及关键基因和酶的研究比较少。文中为进一步开展塑料生物降解研究,寻找高效的塑料降解菌株资源以及进一步在遗传、分子和生化水平研究塑料生物降解机理研究,从而最终实现合成塑料的彻底降解和高值化利用提供了借鉴。     

可降解塑料的微生物降解研究进展

塑料材料的广泛使用给环境带了巨大的污染和处理压力,使用可降解塑料替代传统塑料是解决这一问题的重要途径。可降解塑料的生物降解是由相应的微生物和降解酶来完成的。综述了目前常见的生物降解塑料的微生物降解研究和进展情况,明确了微生物在可降解塑料生物降解中的重要性。     

解塑再用-中欧合作项目“合成塑料降解转化微生物菌群”介绍

中欧环境生物技术合作研究重大项目废弃塑料的生物降解由国家自然科学基金委员会(NationalNatural Science Foundation of China,NSFC)与欧盟委员会(European Commission,EC)共同资助,旨在促使中欧科学家在"Microorganism communities for plastics biodegradation"领域开展实质性合作研究。该项目的目标是将易造成环境污染且难以降解的石化塑料,利用微生物菌群的代谢能力降解为单体小分子并为微生物所用,从而进一步实现高值生物化学品的生物合成。这不仅可以解决塑料污染问题,同时也将塑料垃圾"变废为宝",创造更高的经济效益。中欧合作研究项目将促进双方科学家在合成生物学领域的深入合作,有助于双方建立长期稳定的国际交流与合作关系。中欧双方将致力于解决全球塑料污染问题,形成科技战略力量,共同开启探索不可降解塑料资源化利用领域的新篇章。     

红树林湿地石油降解菌群的构建

近年来海洋污染正在日趋加剧,其中石油污染尤为严重。目前,采用微生物降解是解决海洋石油污染的有效途径之一,而滨海区域的红树林湿地是石油残留聚集和降解的重要生态系统之一。为了构建降解石油的优势菌群,分别以正十六烷烃和萘为唯一碳源,通过富集培养,从受石油污染的红树林淤泥(即土壤)中分离得到2株烷烃降解菌(即Z1、Z3)和2株芳香烃降解菌(即N1、N4)。采用三因素三水平进行正交试验,优化得到降解率最高的菌株组合,并确定了各菌株的最佳投加配比。结果表明:烷烃降解菌Z1、Z3和芳香烃降解菌N1组合的菌群降解石油效果最好,当石油初始质量浓度为2.0 g·L^-1,接种量6%,30℃好氧培养72 h,石油降解率达47.3%;且当N1、Z1、Z3三种菌的投加配比为3:1:3时降解效果最佳,好氧培养72 h,石油降解率达51.2%。     

芘降解菌群驯化过程中的演变

【目的】筛选、驯化获得芘的高效降解菌群,为利用其对多环芳烃污染土壤进行生物修复奠定理论基础。【方法】利用芘作为底物在矿物盐培养基(MSM)中富集驯化,得到了一个混合菌群PYR,利用分光光度计和HPLC测定混合菌群的生长与降解的关系,并对混合菌群降解多环芳烃底物的广谱性和降解芘性能的稳定性进行了测定;通过冷冻干燥的方法对菌群进行了保藏,通过HPLC的方法对保藏后复壮的菌群的降解性能进行了测定;通过培养和非培养方法对菌群的多样性进行了调查,通过构建16S rRNA基因文库的方法,分析焦化厂原始土壤中菌群组成和混合菌群转接3次(PYR-3)、6次(PYR-6)和9次(PYR-9)后的组成变化。【结果】该混合菌群可以利用芘作为唯一碳源和能源生长,12 d对芘的降解率为89%,对于菲(86%)及荧蒽(49%)也具有较高的降解率,但不能降解萘和茚并芘,并且该菌群的降解活性经过多次转接和冷冻干燥保藏保持稳定,从混合菌群中分离得到了9株菌,这9株菌分布在无色杆菌属(Achromobacter),芽胞杆菌属(Bacillus),节杆菌属(Arthrobacter),微小杆菌属(Exiguobacterium)和类土地杆菌属(Parapedobacter)。系统进化分析表明变形菌门是土壤原样(100%)及以芘为底物富集的混合菌群中的主要类群(PYR-3,83%),与原土壤样品相似,PYR-3中γ-Proteobacteria(占变形菌门的77%)中假单胞菌属的菌依然占主导地位,但由于菌群的多样性增加,假单胞菌属所占比例减少。随着富集代数的增加,菌群的多样性进一步增加,γ-Proteobacteria的比例在混合菌群中的比例下降(PYR-6中占变形菌门的33%,PYR-9中占变形菌门的18%),而β-Proteobacteria在混合菌群中的比例上升(PYR-3中占变形菌门的13%,PYR-6中占变形菌门的36%,PYR-9中占变形菌门的55%)。【结论】混合菌群具有很强的芘的降解性能,并且随着传代次数的增加,菌群的组成趋于稳定。     

生物降解塑料PHB的研究概况

论述了生物降解塑料PHB的生产状况、PHB的性能、生物降解性以及PHB在工农业生产特别是在医学领域中的应用。说明PHB在替代化学合成塑料、缓解环境危机和提供新型功能性生物医用材料等方面具有重要意义。     

高效石油降解菌群的构建及对芳香烃化合物萘的协同降解性能

【背景】石油作为一类混杂有机化合物,一旦产生污染就会对人类和环境造成严重的危害。【目的】从新疆石油污染土壤中分离筛选石油降解菌,为石油污染土壤的生物修复提供数据支持及技术参考。【方法】以石油为唯一碳源,通过富集培养、筛选分离得到123株单菌,根据菌落形态挑选出30个不同形态菌株,通过16S rRNA基因序列确定其种属,构建系统发育树;通过原油降解实验筛选出高效石油降解菌,以芳香烃的标志化合物萘为唯一碳源筛选出高效降解菌株,并分别筛选可降解水杨酸、邻苯二酚的菌株。【结果】分离筛选出5株高效石油降解菌,降解率高于85%;萘、水杨酸和邻苯二酚降解菌株各获得一株,将3种菌株按照1:1:1的接种比例对萘进行降解,萘的降解率从单菌60.74%提升到89.40%,菌株间的分工协作可以提高有机物的降解效率。【结论】筛选得到的菌株丰富了石油降解微生物菌种库,不同微生物菌株之间的分工协作为石油污染物的降解提供了新思路,为进一步研究石油污染治理提供参考。     

十溴联苯醚降解菌群的降解特性与组成分析

[目的]针对水体沉积物中日益严重的多溴联苯醚污染问题,以电子垃圾污染河床沉积物为种源富集驯化获得的菌群Cf3,研究该菌群对十溴联苯醚的降解特性以及其菌群结构组成.[方法]通过GC-MS分析十溴联苯醚降解后低溴代产物组成,并测定其降解率;通过DGGE技术分析了该BDE-209降解菌群的结构组成.[结果]菌群Cf3具有较强降解BDE-209的能力,经过120 d的培养,初始量为2.6 μmol的BDE-209降解率达到80.03％,OD600从0.01增长到0.21,pH由初始的6.93增加到反应结束时的8.50.菌群Cf3经过单菌落分离,共获得10株可培养细菌,通过16S rRNA基因序列比对发现,其中6株与柠檬酸杆菌属(Citrobacter spp.)具有较高同源性,其余4株与产碱杆菌属(Alcaligenes spp.)较相似.进一步采用DGGE分析菌群Cf3的结构组成时发现,除了分离得到的2个菌属外,该菌群中还含有拟杆菌属(Wolinella spp.)、氨基酸球菌属(Acidaminococcus spp.),以及随着降解时间延长而消失的脱硫弧菌属(Desulfovibrio spp.)和醋杆菌属(Acetobacterium spp.).[结论]获得了具有较强多溴联苯醚降解能力的菌群,并分析了其降解特性和群落组成,为进一步开展溴代阻燃剂等持久性有机污染物的生物修复提供宝贵的菌种资源和科学数据.     

Degradation of organic pollutants by methane grown microbial consortia

Microbial consortia were enriched from various environmental samples with methane as the sole carbon and energy source. Selected consortia that showed a capacity for co-oxidation of naphthalene were screened for their ability to degrade methyl-tert-butyl-ether (MTBE), phthalic acid esters (PAE), benzene, xylene and toluene (BTX). MTBE was not removed within 24 h by any of the consortia examined. One consortium enriched from activated sludge (AAE-A2), degraded PAE, including (butyl-benzyl)phthalate (BBP), and di-(butyl)phthalate (DBP). PAE have not previously been described as substrates for methanotrophic consortia. The apparent K_m and V_max for DBP degradation by AAE-A2 at 20 °C was 3.1 ± 1.2 mg l^–1 and 8.7 ± 1.1 mg DBP (g protein × h)^–1, respectively. AAE-A2 also showed fast degradation of BTX (230 ± 30 nmol benzene (mg protein × h)^–1 at 20 °C). Additionally, AAE-A2 degraded benzene continuously for 2 weeks. In contrast, a pure culture of the methanotroph Methylosinus trichosporium OB3b ceased benzene degradation after only 2 days. Experiments with methane mono-oxygenase inhibitors or competitive substrates suggested that BTX degradation was carried out by methane-oxidizing bacteria in the consortium, whereas the degradation of PAE was carried out by non-methanotrophic bacteria co-existing with methanotrophs. The composition of the consortium (AAE-A2) based on polar lipid fatty acid (PLFA) profiles showed dominance of type II methanotrophs (83–92% of biomass). Phylogeny based on a 16S-rRNA gene clone library revealed that the dominating methanotrophs belonged to Methylosinus/Methylocystis spp. and that members of at least 4 different non-methanotrophic genera were present (Pseudomonas, Flavobacterium, Janthinobacterium and Rubivivax).     

Biodegradation of a crude oil by three microbial consortia of different origins and metabolic capabilities

Microbial consortia were obtained three by sequential enrichment using different oil products. Consortium F1AA was obtained on a heavily saturated fraction of a degraded crude oil; consortium TD, by enrichment on diesel and consortium AM, on a mixture of five polycyclic aromatic hydrocarbons [PAHs]. The three consortia were incubated with a crude oil in order to elucidate their metabolic capabilities and to investigate possible differences in the biodegradation of these complex hydrocarbon mixtures in relation to their origin. The efficiency of the three consortia in removing the saturated fraction was 60% (F1AA), 48% (TD) and 34% (AM), depending on the carbon sources used in the enrichment procedures. Consortia F1AA and TD removed 100% of n-alkanes and branched alkanes, whereas with consortium AM, 91% of branched alkanes remained. Efficiency on the polyaromatic fraction was 19% (AM), 11% (TD) and 7% (F1AA). The increase in aromaticity of the polyaromatic fraction during degradation of the crude oil by consortium F1AA suggested that this consortium metabolized the aromatic compounds primarily by oxidation of the alkylic chains. The 500-fold amplification of the inocula from the consortia by subculturing in rich media, necessary for use of the consortia in bioremediation experiments, showed no significant decrease in their degradation capability. Journal of Industrial Microbiology & Biotechnology (2002) 28, 252–260 DOI: 10.1038/sj/jim/7000236 Received 12 July 2001/ Accepted in revised form 11 November 2001     

微生物菌群发酵生产化学品的研究进展

廉价生物质资源的利用是工业生物技术领域研究的热点,复杂的成分和较多的杂质使传统的单菌发酵方式难以应对,成为产业化的关键问题。文中从微生物菌群的工业应用、微生物菌群发酵与纯种发酵的比较、微生物细胞间的相互作用等方面综述了微生物菌群发酵技术的最新研究进展,并对微生物菌群的设计和应用进行了展望。微生物菌群发酵可以充分利用廉价生物质基质、生产多个产品或减少副产物的生成,在生物基化学品和燃料的生产中将是一种有前景的发酵技术。     

Biotechnological potential of microbial consortia and future perspectives

Design of a microbial consortium is a newly emerging field that enables researchers to extend the frontiers of biotechnology from a pure culture to mixed cultures. A microbial consortium enables microbes to use a broad range of carbon sources. It provides microbes with robustness in response to environmental stress factors. Microbes in a consortium can perform complex functions that are impossible for a single organism. With advancement of technology, it is now possible to understand microbial interaction mechanism and construct consortia. Microbial consortia can be classified in terms of their construction, modes of interaction, and functions. Here we discuss different trends in the study of microbial functions and interactions, including single-cell genomics (SCG), microfluidics, fluorescent imaging, and membrane separation. Community profile studies using polymerase chain-reaction denaturing gradient gel electrophoresis (PCR-DGGE), amplified ribosomal DNA restriction analysis (ARDRA), and terminal restriction fragment-length polymorphism (T-RFLP) are also reviewed. We also provide a few examples of their possible applications in areas of biopolymers, bioenergy, biochemicals, and bioremediation.     

Artificial microbial consortia for bioproduction processes

The application of artificial microbial consortia for biotechnological production processes is an emerging field in research as it offers great potential for the improvement of established as well as the development of novel processes. In this review, we summarize recent highlights in the usage of various microbial consortia for the production of, for example, platform chemicals, biofuels, or pharmaceutical compounds. It aims to demonstrate the great potential of co-cultures by employing different organisms and interaction mechanisms and exploiting their respective advantages. Bacteria and yeasts often offer a broad spectrum of possible products, fungi enable the utilization of complex lignocellulosic substrates via enzyme secretion and hydrolysis, and microalgae can feature their abilities to fixate CO₂ through photosynthesis for other organisms as well as to form lipids as potential fuelstocks. However, the complexity of interactions between microbes require methods for observing population dynamics within the process and modern approaches such as modeling or automation for process development. After shortly discussing these interaction mechanisms, we aim to present a broad variety of successfully established co-culture processes to display the potential of artificial microbial consortia for the production of biotechnological products.     

合成功能菌群的构建及其工程化应用

自然界中存在着大量的天然微生物群落,不同种群的微生物通过通信及分工拓展了单菌的性能边界,降低了整体的代谢负担并增加了对环境的适应性。合成生物学依据工程设计原理构建或改造基本功能元件、基因线路和底盘细胞,从而对生命的运行过程进行具有目的性的重新编程,获得丰富及可控的生物学功能。将这种工程设计的原理引入菌群,获得结构明确及功能可调的合成群落,可以为合成功能菌群的理论研究到应用提供思路及方法。本文回顾了近年来合成功能菌群领域的相关工作,对合成功能菌群的设计原则、构建方法以及应用进行详细介绍,并对未来的发展进行了展望。     

人工电活性微生物菌群的设计与应用

包括产电菌群和噬电菌群的人工电活性微生物菌群(synthetic electroactive microbial consortia)通过菌种间的物质能量级联反应介导化学能与(光)电能间的相互转化，其可利用底物来源广泛、双向电子传递速率快、环境稳定性强，在清洁电能开发、废水处理、环境修复、生物固碳固氮以及生物燃料、无机纳米材料、高聚物等高值化学品合成等多个领域具有广泛的应用前景。针对人工电活性微生物菌群设计、构建与应用，本文总结电活性微生物菌群界面电子传递和种间电子传递机制，概括基于“劳力分工”原理设计构建人工电活性微生物菌群物质能量级联反应基本架构，总结菌群关系与菌群生态位优化等人工电活性微生物菌群工程化策略，分类列举人工电活性微生物菌群在利用廉价生物质产电、生物光伏固碳产电，光驱噬电生物菌群固氮等相关应用。最后对人工电活性微生物菌群未来研究方向进行了展望。     

Methyl tert-butyl ether biodegradation by microbial consortia obtained from soil samples of gasoline-polluted sites in Mexico

Microbial consortia obtained from soil samples of gasoline-polluted sites were individually enriched with pentane, hexane, isooctane and toluene. Cometabolism with methyl tert-butyl ether, (MTBE), gave maximum degradation rates of 49, 12, 32 and 0 mg g(-1)protein h(-1), respectively. MTBE was fully degraded even when pentane was completely depleted with a cometabolic coefficient of 1 mgMTBE mg(-1)pentane. The analysis of 16S rDNA from isolated microorganisms in the pentane-adapted consortia showed that microorganisms could be assigned to Pseudomonas. This is the first work reporting the cometabolic mineralization of MTBE by consortium of this genus.     

一色齿毛菌对百菌清的生物降解研究

为了验证白腐真菌对杀菌剂——百菌清的降解能力,并初步探讨其降解机制,以平皿培养方式对70株白腐真菌菌株降解百菌清的能力进行验证和筛选,并选择降解作用突出的一色齿毛菌Cerrena unicolor Y4941进行液体培养条件下对百菌清的降解。结果表明:卵菌杀菌剂没有对测试的白腐真菌产生抑制或杀灭作用,在所筛选的70株菌株中,一色齿毛菌Cerrena unicolor Y4941、硬毛粗盖孔菌Funalia trogii W4289、桦褶孔菌Lenzites betulina Y4962、藏红硬孔菌Rigidoporus crocatus D10146、裂褶菌Schizophyllum commune D9466和云芝栓孔菌Trametes versicolor W4614等菌株都对百菌清显示出较强的降解能力;对一色齿毛菌Cerrena unicolor Y4941在液体培养条件下降解百菌清研究的实验结果表明,活菌(living culture,LC)降解率粗酶液(crude enzyme liquor,CEL)降解率灭活菌丝体(devitalized mycelia,DM)降解率,经过活菌降解3d的样品中百菌清的残留率仅为1.92%;对培养液中漆酶活性测定结果显示,漆酶活性最高可达2 195.55U/L。上述证明,杀菌剂百菌清不对白腐真菌产生抑制或杀灭作用,相反,一色齿毛菌Cerrena unicolor Y4941等菌株对其有很强的降解能力,在杀菌剂生物降解领域有潜在的应用前景。