Abstract
Abstract Bacteria with lipolytic activity are widespread in the marine environment. These organisms can be used as a source of lipases with activity in unusual conditions such as low temperatures and high salinities. These characteristics allow them to be applied to several industrial processes and products including wastewater treatment and detergent production. In this context the lipolytic activity of bacteria isolated from deep-sea sediments of the South Atlantic was evaluated. Among the collection studied, two strains, Halomonas sulfidaeris LAMA 838 and Marinobacter excellens LAMA 842, were selected for further analysis concerning their growth and lipolytic activity in different temperatures and culture media. Both strains were characterized as mesophiles: H. sulfidaeris LAMA 838 grew best at 30oC, while M. excellens LAMA 842 showed a maximum growth rate between 20 and 25oC. Maximum lipolytic activity for both microorganisms was observed above 45oC, but only M. excellens LAMA 842 had lipolytic activity at low temperatures (5oC) as well. Considering the culture media employed, H. sulfidaeris LAMA 838 grew better in marine broth without Tween 40, while M. excellens LAMA 842 grew best in marine broth supplemented with Tween 40. Both organisms had maximum lipolytic activity in rich or minimal media supplemented with Tween 40. These results demonstrate the potential of deep-sea bacteria as sources of lipases and indicate conditions that may be used in their cultivation and for the production of industrially relevant enzymes.
Highlights
Lipases are enzymes capable of catalyzing the hydrolysis of long-chain triglycerides to free fatty acids (Treichel et al, 2010), as well as synthesizing esters from glycerol (Lailaja and Chandrasekaran, 2013)
On these data, we were able to select two strains, Halomonas sulfidaeris LAMA 838 and Marinobacter excellens LAMA 842, for further studies. This selection was based on the fact that both strains (1) were able to hydrolyze the four lipid substrates, (2) had high enzymatic index (EI), (3) represent common bacteria cultivated from deep-sea samples (Kumar et al, 2012; Ng et al, 2014; GutiérrezArnillas et al, 2016), and (4) have not been previously reported to be lipolytic species in the scientific literature
Growth was evaluated in different culture media, and the results indicated that the growth rate of the microorganisms studied was highest in nutrient rich media without Tween 40 (T40) (MB) (Barton, 2005), which differed from the enzymatic activity of these microorganisms, for which the best indexes were obtained in media supplemented with Tween (MB+T40 and medium supplemented with 0.5% T40 (MM+T40)), nutrient-rich or minimal
Summary
Lipases are enzymes capable of catalyzing the hydrolysis of long-chain triglycerides to free fatty acids (Treichel et al, 2010), as well as synthesizing esters from glycerol (Lailaja and Chandrasekaran, 2013) These enzymes are used in the food and paper industries, as supplements to detergents, synthesis of biopolymers, production of biodiesel, purification of pharmacologically relevant chemical compounds, cosmetics, agrochemicals, Submitted on: 29/August/2019 Approved on: 11/January/2020 Editor: Rubens M. They are easy to adapt to large scale cultivation and are active in a wide range of pH values and temperatures These features confer high stability and a high specificity for their substrates, and can be attributed to the oligotrophic environments and low temperatures to which these organisms are imposed, as well as the molecules involved in their complex metabolisms. Different marine microorganisms have already been described as extracellular enzyme producers (Odisi et al, 2012)
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