Production of Alkaline Enzymes by Marine Actinobacteria Isolated from Black Sea Sediments

Abstract

Alkaline enzymes obtained from microbial sources find numerous applications in different industrial processes and have commercial value. The aims of the study were to investigate the potential of two actinobacteria (Streptomyces sp. K16 and K19) isolated from Black Sea sediments to produce industrial alkaline enzymes and to characterize their activities under different chemical and physical conditions. The optimal incubation time for the production was determined as 96 h, and by using two actinobacteria respectively 7.91 and 7.94 U mL-1 of activities for amylases, 0.55 and 0.82 U mL-1 for lipases and 3.07 and 2.34 U mL-1 for proteases were obtained. The optimal pH and temperature values for the enzymes were found to be pH 8.0 and 37°C. All the enzymes exhibited stability in different quantities after the incubation at pH values ranging from 3.0 and 10.0 for 2 h. On the other hand, the lipases remained stable up to 50°C although the amylases and proteases showed stability in varying ratios after 2 h incubation under the tested temperatures. In the light of the findings, the actinobacteria and their enzymes are thought to have potential for further studies.

Bioprospecting for Novel Bacterial Sources of Hydrolytic Enzymes and Antimicrobials in the Romanian Littoral Zone of the Black Sea

“…The growth temperature interval of the recovered marine bacteria was also variable (Figure 5), with the highest number of strains (25) able to grow in the 4-40 • C interval, and others in a more restrained range of 4-35 • C (16 strains) and 4-30 • C (13 strains). At 4 • C, the majority of the isolates grew slowly (>3-4 days), and eight strains required incubation temperatures above 10 • C. A limited number of strains, mainly belonging to the classes Bacilli and Actinobacteria, could grow at temperatures up to 50 • C (6 strains) and 55 • C (2 strains) (Figure 5).…”

“…The great effort to elucidate the ecological roles of microorganisms inhabiting this unique environment was, however, counterbalanced by a lack of studies aiming to explore their biotechnological potential. To our knowledge, relatively few investigations carried out in the Black Sea have targeted the discovery of novel valuable metabolites such as enzymes [25,26] and bioactive molecules [27,28].…”