Newly Isolated Alkane Hydroxylase and Lipase Producing Geobacillus and Anoxybacillus Species Involved in Crude Oil Degradation

Durratul Fatini Yusoff,Raja Noor Zaliha Raja Abd Rahman,Mohd Shukuri Mohamad Ali,Thean Chor Leow,Malihe Masomian

doi:10.3390/catal10080851

Durratul Fatini Yusoff, Raja Noor Zaliha Raja Abd Rahman + Show 3 more

Open Access

https://doi.org/10.3390/catal10080851

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Journal: Catalysts	Publication Date: Aug 1, 2020
Citations: 15	License type: CC BY 4.0

Affiliation: Universiti Putra Malaysia, Sunway University

Abstract

Isolation and studies of novel, crude oil biodegrading thermophilic strains may provide a wider knowledge in understanding their role in petroleum degradation. In this study, the screening of ten new thermophilic strains revealed that all strains were alkane hydroxylase producers and seven of them produced lipase concurrently. Three best strains were characterized and identified through 16S rRNA sequence analysis as Geobacillus sp. D4, Geobacillus sp. D7, and Anoxybacillus geothermalis D9 with GenBank accession numbers MK615934.1, MK615935.1, and MK615936.1, respectively. Gas chromatography (GC) analysis showed that all three strains were able to breakdown various compounds in crude oil such as alkanes, toxic poly-aromatic hydrocarbons (PAHs), organosulfur, carboxylic acids, alkene, resins, organosilicon, alcohol, organochlorine, and ester. For the first time, alkane hydroxylase and lipase activity as well as crude oil degradation by A. geothermalis species were reported. Geobacillus sp. D7 is the best alkane degrader followed by A. geothermalis D9 and Geobacillus sp. D4 with 17.3%, 13.1%, and 12.1% biodegradation efficiency (BE%), respectively. The potential of thermophiles isolated can be explored further for bioremediation of sites polluted by petroleum and oil spills.

Highlights

Crude oil hydrocarbons are considered as one of the organic pollutants of high concern due to their wide distribution and persistence in nature [1,2,3]
23 thermophilic bacteria that are able to utilize crude oil as a sole carbon source were isolated from seawater and soil
Isolate D3 only grew after two days of incubation (Figure 1a) which indicates that D3 might be a slow-growing bacterium. pH analysis of the culture medium shows an increase of alkalinity from the initial pH of 7.5 for all ten isolates once the bacteria cells proliferate

Summary

Introduction

Crude oil hydrocarbons are considered as one of the organic pollutants of high concern due to their wide distribution and persistence in nature [1,2,3]. The presence of complex compounds in crude oil such as alkanes, monocyclic, and polycyclic aromatic hydrocarbons causes toxicity to the environment and human health [2,4,5]. Crude oil biodegradation has been widely studied for the past few decades [6,7,8,9]. These studies have led to numerous microorganisms and their enzymes to be isolated and characterized. Catalysts 2020, 10, 851 components of crude oil, can be broken down aerobically by groups of cooperative enzymes such as alkane hydroxylase, alcohol dehydrogenase, aldehyde dehydrogenase, esterase, and lipase [10,11].

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