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塑料制品在当今世界的用途十分广泛,但高聚物的结构也使得废弃后的塑料成为了地球上的一大污染物,对海洋生物、水质、土壤等生境造成了极大地负面影响[1]。在这样严峻的形势下,如何降解塑料则成为了治理环境污染的研究热点。通常高聚物的降解方式有光氧化、臭氧诱发、催化降解及生物降解等,其中生物降解是最为环保绿色的降解方式。
黄粉虫(Tenebrio molitor)是昆虫纲、鞘翅目、拟步甲科、粉甲属的一个物种,其食性杂,可取食纤维素含量高的材料,有研究报道黄粉虫可降解塑料[2]。除此之外,在土壤中也分离得到了多种对塑料有降解效果的菌株[3]。这些发现都可为未来解决塑料垃圾污染问题提供有力支撑。
本研究以黄粉虫和土壤为研究材料,对黄粉虫肠道菌进行分离,同时对土壤环境中的菌株进行分离。通过对液体培养基中的塑料进行切片观察和以塑料为唯一碳源对菌体浓度进行测定,来筛选对聚苯乙烯泡沫塑料和聚乳酸塑料有降解特性的菌株,并尝试模拟混菌体系。
几株细菌对聚苯乙烯泡沫及聚乳酸的降解性能
Degradation of polystyrene foam and polylactic acid by several strains of bacteria
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摘要: 由于塑料的大量使用,并且大部分塑料在自然界中难以降解,使得塑料垃圾对环境造成了巨大的负面影响。本研究从黄粉虫肠道和土壤分离能降解聚苯乙烯泡沫及聚乳酸塑料的菌株。黄粉幼虫以6∶1的麸皮与塑料配比饲喂21 d,对其肠道菌株进行分离、培养。同时对混杂有破裂、发脆、老化塑料的土壤菌株进行分离、培养。而后利用扫描电镜切片观察和菌数量测定,筛选对聚苯乙烯泡沫及聚乳酸这两种塑料有降解特性的菌株。最后设计混菌体系,优化出最佳的降解组合。结果从黄粉虫肠道和土壤中分离筛选出5种降解效果好的菌株,分别为Klebsiella sp.G-1、Klebsiella pneumoniae strain PLA-2、Klebsiella pneumoniae subsp. N-2、Bacterium strain G-2和Escherichia coli strain L-1。并得到5个对聚苯乙烯泡沫降解性更好的混菌体系:A5(Klebsiella pneumoniae strain PLA-2、Klebsiella pneumoniae subsp. N-2)、A10(Escherichia coli strain L-1、Bacterium strain G-2)、B1(Klebsiella sp. G-1、Klebsiella pneumoniae strain PLA-2、Klebsiella pneumoniae subsp. N-2)、B2(Klebsiella sp. G-1、Klebsiella pneumoniae strain PLA-2、Escherichia coli strain L-1)和C4(Klebsiella sp. G-1、Klebsiella pneumoniae subsp. N-2、Escherichia coli strain L-1、Bacterium strain G-2)。研究结果表明,黄粉虫肠道及土壤环境中存在对聚苯乙烯泡沫及聚乳酸塑料有一定降解性的细菌,且混菌体系对聚苯乙烯泡沫的降解效果要优于单株菌。Abstract: Plastics were used in large quantities and difficult to degrade in nature, making plastic waste have a huge negative impact on the environment. Strains which can degrade polystyrene foam and polylactic acid plastics were isolated from tenebrio molitor gut and soil mixed with cracked, brittle and aged plastic. The tenebrio molitors were feed with bran and plastics at a ratio of 6∶1 for 21 days and the gut bacteria were isolated and cultured. Plastic section and the cell concentration were used to investigate the characteristics of plastic degradation. Finally, the mixed bacteria system was designed to optimize the degradation. The results shown that five strains with good degradation effect were screened from the intestinal tract and soil, which were Klebsiella sp.G-1、Klebsiella pneumoniae strain PLA-2、Klebsiella pneumoniae subsp. N-2、Bacterium strain G-2 and Escherichia coli strain L-1. Meanwhile, five mixed bacteria systems [A5 (Klebsiella pneumoniae strain PLA-2、Klebsiella pneumoniae subsp. N-2)、A10 (Escherichia coli strain L-1、Bacterium strain G-2)、B1 (Klebsiella sp. G-1、Klebsiella pneumoniae strain PLA-2、Klebsiella pneumoniae subsp. N-2)、B2 (Klebsiella sp. G-1、Klebsiella pneumoniae strain PLA-2、Escherichia coli strain L-1) and C4 (Klebsiella sp. G-1、Klebsiella pneumoniae subsp. N-2、Escherichia coli strain L-1、Bacterium strain G-2)] with good degradation effect were also obtained through mixing and matching. The results suggested that strains which can degrade polystyrene foam and polylactic acid plastics could been isolated from tenebrio molitor gut and soil, the degradation of polystyrene foam by mixed bacteria system was better than single bacteria.
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Key words:
- Tenebrio molitor /
- soil /
- polystyrene foam /
- polylactic acid
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图 4 各菌株(Klebsiella sp. G-1、Klebsiella pneumoniae strain PLA-2、Klebsiella pneumoniae subsp. N-2、Bacterium strain G-2、Escherichia coli strain L-1)基于16S rRNA基因序列的系统发育进化树
Figure 4. Phylogenetic tree of strain ( Klebsiella sp. G-1,Klebsiella pneumoniae strain PLA-2,Klebsiella pneumoniae subsp. N-2,Bacterium strain G-2,Escherichia coli strain L-1)based on 16S rRNA gene sequence
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[1] 李蕾, 李彦澄, 刘邓平, 等. 基于甲烷氧化菌的难降解有机物生物降解研究进展 [J]. 环境化学, 2020, 39(2): 467-74. doi: 10.7524/j.issn.0254-6108.2019081002 LI L, LI Y C, LIU D P, et al. Advancement overviews on methanotrph-based biodegradation of refractory organics [J]. Environmental Chemistry, 2020, 39(2): 467-74(in Chinese). doi: 10.7524/j.issn.0254-6108.2019081002
[2] 陈建兴, 郭成, 李静, 等. 黄粉虫的生物降解功能研究进展 [J]. 赤峰学院学报, 2018, 34(4): 42-44. CHEN J X, GUO C, LI J, et al. Research progress on biodegradation function of tenderfly [J]. Journal of Chifeng University, 2018, 34(4): 42-44(in Chinese).
[3] 张金宝, 李凤梅, 郭书海, 等. 高分子量多环芳烃降解菌筛选及在土壤电动-生物修复中应用 [J]. 生态学杂志, 2020, 39(1): 260-269. ZHANG J B, LI F M, GUO S H, et al. Isolation of high molecular weight PAHs degrading bacteria and its application in the electro- bioremediation of contaminated soil [J]. Chinese Journal of Ecology, 2020, 39(1): 260-269(in Chinese).
[4] 孔芳, 洪康进, 徐航, 等. 基于啮食泡沫塑料黄粉虫肠道菌群中聚苯乙烯生物降解的探究 [J]. 微生物学通报, 2018, 45(7): 1438-1449. KONG F, HONG K J, XU H, et al. Evidence of polystyrene biodegradation by gut microbiota of Styrofoam-feeding yellow mealworms [J]. Microbiology China Tongbao, 2018, 45(7): 1438-1449(in Chinese).
[5] 周德庆. 微生物学教程[M]. 北京: 高等教育出版社, 2011: 87-88. ZHOU D Q. Microbiology course [M]. Beijing: Higher Education Press, 2011: 87-88 (in Chinese).
[6] 周德庆, 徐德强. 微生物学实验教程[M]. 北京: 高等教育出版社, 2013: 30-32. ZHOU D Q, XU D Q. Microbiology experiment course[M]. Beijing: Higher Education Press, 2013: 30-32 (in Chinese).
[7] SIPOS R, SZEKELY A J, PALATINSZKY M, et al. Effect of primer mismatch, annealing temperature and PCR cycle number on 16S rRNA gene-targetting bacterial community analysis [J]. FEMS Microbiology Ecology, 2007, 60(2): 341-350. doi: 10.1111/j.1574-6941.2007.00283.x [8] 张可, 胡芮绮, 蔡珉敏, 等. 黄粉虫取食和消化降解PE塑料薄膜的研究 [J]. 化学与生物工程, 2017, 34(4): 47-49. doi: 10.3969/j.issn.1672-5425.2017.04.011 ZHANG K, HU R Q, CAI M M, et al. Degradation of plastic film containing polyethylene (PE) by yellow meal worms [J]. Chemistry & Bioengineering, 2017, 34(4): 47-49(in Chinese). doi: 10.3969/j.issn.1672-5425.2017.04.011
[9] 沈叶红. 黄粉虫肠道菌的分离和取食塑料现象的研究[D]. 上海: 华东师范大学, 2011. SHEN Y H. Isolation of intestinal bacteria from T. molitor L and study on the phenomenon of plastic degradation[D]. Shanghai: East China Normal University, 2011 (in Chinese).
[10] YANG Y, YANG J, WU W M, et al. Biodegradation and mineralization of polystyrene by plastic-eating mealworms: Part 1. Chemical and physical characterization and isotopic tests [J]. Environmental Science & Technology, 2015, 49(20): 12080-12086. [11] YANG Y, YANG J, WU W M, et al. Biodegradation and mineralization of polystyrene by plastic-eating mealworms: Part 2. Role of gut microorganisms [J]. Environmental Science & Technology, 2015, 49(20): 12087-12093. [12] 冯静. 白浅灰链霉菌对聚乙烯降解效果研究及降解酶的基因克隆[D]. 成都: 四川师范大学, 2016. FENG J. The study on the degradation of polyethylene by Streptomyces albogriseolus and degradation enzyme gene cloning[D]. Chengdu: Sichuan Normal University, 2016 (in Chinese).
[13] 钟越, 李雨竹, 张榕麟, 等. 一株聚乙烯降解菌的筛选及其降解特性研究 [J]. 生态环境学报, 2017, 26(4): 681-686. ZHONG Y, LI Y Z, ZHANG R L, et al. Screening a polyethylene degrading strain and study on the degradation characteristics [J]. Ecology and Environmental Sciences, 2017, 26(4): 681-686(in Chinese).
[14] GILBERT E S, WALKER A W, KEASLING J D. A constructed microbial consortium for biodegradation of the organophosphorus insecticide parathion [J]. Applied Microbiology Biotechnology, 2003, 61: 77-81. doi: 10.1007/s00253-002-1203-5 [15] MINTY J J, SINGER M E, SCHOLZ S A, et al. Design and characterization of synthetic fungal-bacterial consortia for direct production of isobutanol from cellulosic biomass [J]. National Academy of Sciences, 2013, 110(36): 14592-14597. doi: 10.1073/pnas.1218447110 [16] BRENNER K, YOU L, ARNOLD F H. Engineering microbial consortia: a new frontier in synthetic biology [J]. Trends in Biotechnology, 2008, 26: 483-489. doi: 10.1016/j.tibtech.2008.05.004