Effect of calcium ions to the activity and stability of extracellular lipase produced by moderate halophilic bacteria Halomonas meridiana BK-AB4

• Main Authors: Nanda, Galo Ayu Megga, Hertadi, Rukman
• Format: Article
• Language: English
• Published: Penerbit Universiti Kebangsaan Malaysia 2020
• Online Access: http://journalarticle.ukm.my/16021/1/49_02_05.pdf; http://journalarticle.ukm.my/16021/; http://www.mabjournal.com/index.php?option=com_content&view=article&id=1003&catid=59:current-view&Itemid=56

This study reported the isolation and biochemical studies of extracellular lipase produced by a moderate halophilic bacterium, Halomonas meridiana BK-AB4. The estimated molecular weight of the lipase BK-AB4 is about 50 kDa. The study of metal ions effect to the enzyme activity revealed the strong dependency towards the presence of Ca2+ ion. Further studies showed that the optimum pH of the enzyme was similar in the presence and the absence of Ca2+ ions. However, the presence of Ca2+ ions could improve the enzyme thermal stability as indicated by the shift of its optimum temperature from 45°C - 50°C. The addition of Ca2+ ions was also enhancing residual activity towards various inhibitors, such as SDS and PMSF up to 55% and 68%, respectively. Another interesting effect of the addition of Ca2+ ions were noted when various organic solvents were added to the enzyme solution in the ratio of 1:1. The activity of the enzyme increased up to 122% and 126% relative to the control when methanol and n-butanol were added, respectively. This study thus showed that the addition of Ca2+ ion not only improved the catalytic activity of lipase BK-AB4 but also made the enzyme more tolerable against various perturbations.