Studies of action of heavy metals on caffeine degradation by immobilised <i>Leifsonia sp.</i> strain SIU

Abstract

Caffeine is an important naturally occurring compound that can be degraded by bacteria. Excessive caffeine consumption is known to have some adverse problems. Previously, Leifsonia sp. strain SIU capable of degrading caffeine was isolated from agricultural soil. The bacterium was tested for its ability to degrade caffeine as the sole carbon and nitrogen source. The isolate was encapsulated in gellan gum and its ability to degrade caffeine in the presence of heavy metals was determined. Out of the nine heavy metals tested, Copper (Cu), Mercury (Hg), and Silver (Ag) had significant effects on caffeine degradation at 1mg/L. Therefore, the concentration of these heavy metals was varied from 0 -1 mg/L to see at what concentration each metal it has effect. Ag and Hg showed effect at 0.1 mg/L with caffeine degradation of 64.05 and 52.17% respectively, while Cu showed effect at 0.8 mg/L with caffeine degradation of 64.74%. These bacterium features make it an ultimate means for caffeine bioremediation. This is the first report of effect of heavy metals on caffeine degradation by immobilised Leifsonia sp. strain SIU.

The effect of heavy metals on biodegradation of carbofuran by microbial strain enriched from Agricultural areas

“…Radjendirane et al (1991) showed that mercury can hinder hydroxylases activity like aryl 2,4-dichlorophenol hydroxylase and 3-hydroxybenzoate-6-hydroxylase. Ibrahim et al (2015) found that concentrations of mercury from 0.1 to 1 mg/L affected the degradation of caffeine by Leifsonia sp. isolated from soil.…”

Enhanced Carbofuran Degradation Using Immobilized and Free Cells of Enterobacter sp. Isolated from Soil

“…Reports by Radjendirane et al [ 37 ] showed that mercury could hinder hydroxylases activity like aryl 2,4-dichlorophenol hydroxylase and 3-hydroxybenzoate-6-hydroxylase. In another study by Ibrahim et al [ 35 ], the authors found that concentrations of mercury from 0.1 to 1 mg/L affected the degradation of caffeine by Leifsonia sp. isolated from soil.…”

“…Molecules 2020, 25, x FOR PEER REVIEW 7 of 13 sites are co-contaminated with organic and metal pollutants. Data from both aerobic and anaerobic systems show that biodegradation of the organic compound may be reduced by metal toxicity [31,[35][36][37]. Widespread use of pesticides and fertilizers may also have led to the presence of heavy metals in soil.…”

Effect of heavy metals and other xenobiotics on biodegradation of waste canola oil by cold-adapted Rhodococcus sp. strain AQ5-07

“…Mercury toxicity to bioremediation activity can be reduced by the addition of metal immobilising agents (Yusuf et al, 2019). Ibrahim et al (2016) reported that immobilised Leifsonia sp. strain SIU can withstand up to 0.4 ppm Hg in caffeine degradation, helping to reduce Hg toxicity and maintaining the function of the bioremediation agent even in a polluted environment.…”

“…Cd also inhibits the biodegradation of other xenobiotics (Hoffman et al, 2005;Sandrin and Maier, 2003). The inhibitory effect of Cd can be lessened by immobilising the bacteria (Ahmad et al, 2017;Ibrahim et al, 2016). Furthermore, the addition of chemical additives can reduce the toxicity of cadmium ions (El-Deeb and Altalhi, 2009).…”