Investigation of kinetics in bioaugmentation of crude oil via high- throughput sequencing: Enzymatic activities, bacterial community composition and functions

The enzymes and the characteristics of the community of the petroleum-degrading bacteria play a crucial role in the crude oil biodegradation. The prediction of kinetics of the key groups of hydrocarbons in crude oil was important to evaluate the bioremediation speed and constant. Most of the n-alkanes (C9-C29) were degraded in 25 days, and the average degradation rates of C18-C27 higher than 100 mg g-1d-1. The hopanes, such as H30, had a biodegradation rate more than 10 mg g-1d-1. The related enzymes ac-tivities changed along with the crude oil biodegradation, especially dehydrogenase. The 16S rRNA gene amplicon sequencing revealed that Proteobacteria, Firmcutes, Bacteroidetes, Actinobacteria, Acid-obacteria were the main petroleum hydrocarbon degraders during the crude oil biodegradation, and the top two highest relative abundance of the genera were Alcaligenes and Acinetobacter. Acinetobacter presented positive correlation to biodegradation of n-alkanes and PAHs. Based on COG analysis, the largest group involved in the general function was amino acid transport and metabolism. The functional categories of bacterial communities were mainly focused on the carbohydrate and amino acid meta-bolism, xenobiotics biodegradation and metabolism, membrane transport, and so on. Overall, these findings highlight the potential guideline for more adequate monitoring of microbial degradation of crude oil.(c) 2022 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

Automated summary

Enzymes and characteristics of petroleum-degrading bacteria are crucial for crude oil biodegradation. The study reveals that Proteobacteria, Firmcutes, and other bacterial groups play a significant role in petroleum hydrocarbon degradation. Acinetobacter shows a strong correlation with the degradation of n-alkanes and PAHs. Additionally, functional categories related to carbohydrate and amino acid metabolism, xenobiotic biodegradation, and membrane transport are important in bacterial communities.