Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy.
Task Force on Microbiome Studies, University of Naples Federico II, Naples, Italy.
Microbiome. 2023 Sep 14;11(1):205. doi: 10.1186/s40168-023-01649-0.
In the last few years, considerable attention has been focused on the plastic-degrading capability of insects and their gut microbiota in order to develop novel, effective, and green strategies for plastic waste management. Although many analyses based on 16S rRNA gene sequencing are available, an in-depth analysis of the insect gut microbiome to identify genes with plastic-degrading potential is still lacking.
In the present work, we aim to fill this gap using Black Soldier Fly (BSF) as insect model. BSF larvae have proven capability to efficiently bioconvert a wide variety of organic wastes but, surprisingly, have never been considered for plastic degradation. BSF larvae were reared on two widely used plastic polymers and shotgun metagenomics was exploited to evaluate if and how plastic-containing diets affect composition and functions of the gut microbial community. The high-definition picture of the BSF gut microbiome gave access for the first time to the genomes of culturable and unculturable microorganisms in the gut of insects reared on plastics and revealed that (i) plastics significantly shaped bacterial composition at species and strain level, and (ii) functions that trigger the degradation of the polymer chains, i.e., DyP-type peroxidases, multicopper oxidases, and alkane monooxygenases, were highly enriched in the metagenomes upon exposure to plastics, consistently with the evidences obtained by scanning electron microscopy and H nuclear magnetic resonance analyses on plastics.
In addition to highlighting that the astonishing plasticity of the microbiota composition of BSF larvae is associated with functional shifts in the insect microbiome, the present work sets the stage for exploiting BSF larvae as "bioincubators" to isolate microbial strains and enzymes for the development of innovative plastic biodegradation strategies. However, most importantly, the larvae constitute a source of enzymes to be evolved and valorized by pioneering synthetic biology approaches. Video Abstract.
在过去的几年中，人们对昆虫及其肠道微生物群在塑料降解方面的能力给予了极大的关注，以期开发出新型、有效且环保的塑料废物管理策略。尽管已经有许多基于 16S rRNA 基因测序的分析，但对昆虫肠道微生物组进行深入分析以确定具有塑料降解潜力的基因仍然缺乏。
在本工作中，我们使用黑腹果蝇（BSF）作为昆虫模型来填补这一空白。BSF 幼虫已被证明具有高效生物转化各种有机废物的能力，但令人惊讶的是，它们从未被考虑用于塑料降解。BSF 幼虫在两种广泛使用的塑料聚合物上进行饲养，并利用鸟枪法宏基因组学来评估含塑料饮食是否以及如何影响肠道微生物群落的组成和功能。BSF 肠道微生物组的高清晰度图谱首次揭示了在塑料上饲养的昆虫肠道中可培养和不可培养微生物的基因组，并揭示了（i）塑料在物种和菌株水平上显著塑造了细菌的组成，（ii）触发聚合物链降解的功能，即 DyP 型过氧化物酶、多铜氧化酶和烷烃单加氧酶，在暴露于塑料时在宏基因组中高度富集，这与扫描电子显微镜和 H 核磁共振分析对塑料的研究结果一致。
除了强调 BSF 幼虫惊人的微生物群落组成的可塑性与昆虫微生物组的功能转变有关之外，本工作还为利用 BSF 幼虫作为“生物孵化器”来分离微生物菌株和酶以开发创新的塑料生物降解策略奠定了基础。然而，最重要的是，幼虫是酶的来源，可以通过开拓性的合成生物学方法进行进化和利用。
