Characterization of a chitinase with antifungal activity from a native Serratia marcescens B4A

Abstract

Chitinases have the ability of chitin digestion that constitutes a main compound of the cell wall in many of the phytopathogens such as fungi. In the following investigation, a novel chitinase with antifungal activity was characterized from a native Serratia marcescens B4A. Partially purified enzyme had an apparent molecular mass of 54 kDa. It indicated an optimum activity in pH 5 at 45ºC. Enzyme was stable in 55ºC for 20 min and at a pH range of 3-9 for 90 min at 25ºC. When the temperature was raised to 60ºC, it might affect the structure of enzymes lead to reduction of chitinase activity. Moreover, the Km and Vmax values for chitin were 8.3 mg/ml and 2.4 mmol/min, respectively. Additionally, the effect of some cations and chemical compounds were found to stimulate the chitinase activity. In addition, Iodoacetamide and Idoacetic acid did not inhibit enzyme activity, indicating that cysteine residues are not part of the catalytic site of chitinase. Finally, chitinase activity was further monitored by scanning electronic microscopy data in which progressive changes in chitin porosity appeared upon treatment with chitinase. This enzyme exhibited antifungal activity against Rhizoctonia solani, Bipolaris sp, Alternaria raphani, Alternaria brassicicola, revealing a potential application for the industry with potentially exploitable significance. Fungal chitin shows some special features, in particular with respect to chemical structure. Difference in chitinolytic ability must result from the subsite structure in the enzyme binding cleft. This implies that why the enzyme didn't have significant antifungal activity against other Fungi

Potential of Chitinolytic Bacillus amyloliquefaciens SAHA 12.07 and Serratia marcescens KAHN 15.12 as Biocontrol Agents of Ganoderma boninense

“…Chitinase activity at temperature 20°C was only found on S. marcescens KAHN 15.12 although, it was lower than the optimum temperature. The same result also reported that chitinase had optimum activity between 35-75°C (Wang et al, 2002;Dai et al, 2011;Tu et al, 2010;Zarei et al, 2011;Asril et al, 2014;Laribi-Habchi et al, 2015).…”

“…This occurred because of S. marcescens KAHN 15.12 had a chitinase specific activity that was higher than B. amyloliquefaciens SAHA 12.07, it was alleged the ability to lyse G. boninense cell wall will be higher and NAG will be produced in the higher number. This is supported that Serratia marcescens has also known as a potential chitinase producing bacteria that has been widely applied as biocontrol (Tu et al, 2010;Zarei et al, 2011;Okay et al, 2013;Fadhil et al, 2014). In the condition above optimum time, here concentration of NAG decreased.…”

“…One of chitinase fungsion as an antifungal which effective and widely used as biocontrol agents of fungal pathogens (Singh et al, 1999;Wang et al, 2002;Zarei et al, 2011;Dai et al, 2011;Patil et al, 2013;Fadhil et al, 2014). Chitinase can be produced by bacteria, fungi, insects and plants.…”

Optimization, purification, and characterization of an extracellular antifungal protein from Serratia marcescens DT3 isolated from soil in Vietnam

“…This conclusion was also reported in previous studies of other strains of Serratia sp. (Parani et al, 2011;Zarei et al, 2011) …”

“…Purified antifungal proteins from different Serratia sp. strains have different molecular weights that range from 47 to 62 kDa (Roberts and Cabib, 1982;Frankowski et al, 2001;Kamens et al, 2003;Zarei et al, 2011;Babashpour et al, 2012;Fadhil et al, 2014). The final yield of the purification procedure was 28% (Table 2).…”