Identification of a carboxylesterase-producing Rhodococcus soil isolate

Area of Science:

• Microbiology
• Biotechnology
• Enzymology

Background:

• Subtropical soil harbors diverse microbial communities with potential enzymatic activities.
• Lipolytic enzymes are crucial for various biotechnological processes, including synthesis and degradation.
• Screening soil isolates is a common strategy for discovering novel enzymes and microorganisms.

Purpose of the Study:

• To screen subtropical soil microbial isolates for hydrolytic enzyme activity.
• To isolate and characterize a strain with significant lipolytic activity.
• To evaluate the potential biotechnological applications of the identified strain and its enzymes.

Main Methods:

• Agar plate screening using carbohydrate, tributyrin, and olive oil substrates.
• Morphological and physiological characterization of selected isolates.
• 16S rDNA sequencing for precise microbial identification.
• Zymogram analysis to confirm and characterize enzyme activity.

Main Results:

• A heterotrophic, aerobic, Gram-positive strain exhibiting tributyrin hydrolysis was isolated.
• The strain was identified as Rhodococcus erythropolis with 99% 16S rDNA sequence identity.
• The isolate demonstrated lipolytic activity on short-chain fatty-acid derivatives, with intracellular enzyme activity concentrated in cell extracts.
• A ca. 60-kDa intracellular protein band with lipolytic activity was identified via zymogram analysis.

Conclusions:

• The identified Rhodococcus erythropolis strain possesses significant lipolytic capabilities.
• The presence of a specific intracellular lipolytic enzyme suggests potential for industrial applications.
• This strain could be valuable for pharmaceutical synthesis and biocide detoxification processes.