Department of Biotechnology and Biochemistry, University of Zimbabwe, Harare, Zimbabwe.
BMC Biotechnol. 2022 Jan 4;22(1):2. doi: 10.1186/s12896-021-00733-3.
The excessive use of polystyrene as a packaging material has resulted in a rise in environmental pollution. Polystyrene waste has continually increased water pollution, soil pollution and the closing of landfill sites since it is durable and resistant to biodegradation. Therefore, the challenge in polystyrene disposal has caused researchers to look for urgent innovative and eco-friendly solutions for plastic degradation. The current study focuses on the isolation and identification of bacteria produced by the larvae of beetle Tenebrio molitor (yellow mealworms), that enable them to survive when fed with polystyrene foam as their sole carbon diet.
The biodegradation of polystyrene by Tenebrio molitor was investigated by breeding and rearing the mealworms in the presence and absence of polystyrene. A comparison was made between those fed with a normal diet and those fed on polystyrene. The mealworms which were fed with polystyrene were then dissected and the guts were collected to isolate and identify the bacteria in their guts. The viability and metabolic activity of the isolates were investigated. The polymerase chain reaction (PCR) followed by sequencing was used for molecular identification of the isolates. The PCR products were directly sequenced using Sanger's method and the phylogenetic tree and molecular evolutionary analyses were constructed using MEGAX software with the Neighbour Joining algorithm. The evolutionary distances were computed using the Maximum Composite Likelihood method.
The decrease in mass of the polystyrene as feedstock confirmed that the mealworms were depending on polystyrene as their sole carbon diet. The frass egested by mealworms also confirmed the biodegradation of polystyrene as it contained very tiny residues of polystyrene. Three isolates were obtained from the mealworms guts, and all were found to be gram-negative. The sequencing results showed that the isolates were Klebsiella oxytoca ATCC 13182, Klebsiella oxytoca NBRC 102593 and Klebsiella oxytoca JCM 1665.
Klebsiella oxytoca ATCC 13182, Klebsiella oxytoca NBRC 102593 and Klebsiella oxytoca JCM 1665 maybe some of the bacteria responsible for polystyrene biodegradation.
作为一种包装材料，聚苯乙烯的过度使用导致了环境污染的增加。由于聚苯乙烯具有耐用性和抗生物降解性，它不断增加水污染、土壤污染和垃圾填埋场的关闭。因此，聚苯乙烯处理的挑战促使研究人员寻找塑料降解的紧急创新和环保解决方案。本研究关注的是从甲虫黄粉虫（黄粉虫）幼虫中分离和鉴定出的细菌，这些细菌能够在以聚苯乙烯泡沫为唯一碳源的情况下生存。
通过在有和没有聚苯乙烯的情况下饲养和饲养黄粉虫来研究黄粉虫对聚苯乙烯的生物降解。将那些用正常饮食喂养的和那些用聚苯乙烯喂养的进行了比较。然后将用聚苯乙烯喂养的黄粉虫解剖，收集肠道以分离和鉴定肠道中的细菌。研究了分离物的生存能力和代谢活性。采用聚合酶链反应（PCR）测序对分离物进行分子鉴定。PCR 产物直接用 Sanger 法测序，用 MEGAX 软件构建系统发育树和分子进化分析，采用邻接法。进化距离采用最大复合似然法计算。
作为饲料的聚苯乙烯质量的减少证实了黄粉虫依赖聚苯乙烯作为其唯一的碳源。黄粉虫排出的粪便也证实了聚苯乙烯的生物降解，因为它含有非常小的聚苯乙烯残留。从黄粉虫肠道中获得了三个分离物，所有分离物均为革兰氏阴性菌。测序结果表明，这些分离物分别为产酸克雷伯菌 ATCC 13182、产酸克雷伯菌 NBRC 102593 和产酸克雷伯菌 JCM 1665。
产酸克雷伯菌 ATCC 13182、产酸克雷伯菌 NBRC 102593 和产酸克雷伯菌 JCM 1665 可能是导致聚苯乙烯生物降解的部分细菌。
