Agroresidues enhanced peroxidase activity expression by Bacillus sp. MABINYA-1 under submerged fermentation

Abstract

Abstract Agroresidues have continued to gain preference over conventional carbon sources for microbial enzyme production due to the low price and abundance in the environment. Therefore, this study aimed at improving peroxidase yield by Bacillus sp. MABINYA-1 (BMAB-1) using agroresidues under submerged fermentation. The culture parameters that support maximum peroxidase yield by BMAB-1 was initially determined and the results showed that peroxidase activity expression was optimum at pH 5, 30 °C and 150 rpm while veratryl alcohol and ammonium sulphate served as the best peroxidase-inducer and inorganic nitrogen source, respectively. BMAB-1 exhibited maximum peroxidase expression (17.50 ± 0.10 U/mg) at 72 h using kraft lignin liquid medium (KLLM) under the optimized culture conditions. Upon utilization of selected agroresidues (sawdust, wheat straw and maize stover) as sole carbon sources by BMAB-1 in the fermentation process, peroxidase activity was significantly enhanced when compared with glucose (14.91 ± 0.31 U/mg) and kraft lignin (17.50 ± 0.10 U/mg). Sawdust produced the highest peroxidase yield (47.14 ± 0.41 U/mg), followed by maize stover (37.09 ± 0.00 U/mg) while wheat straw yielded the lowest peroxidase specific activity (21.65 ± 0.35 U/mg). This indicates that utilization of sawdust by BMAB-1 resulted in 3.2- and 2.7-fold increase in peroxidase activity expression as compared to glucose and kraft lignin, respectively. The aptitude of BMAB-1 to utilize agroresidues would reduce the cost of peroxidase production by the bacteria since the substrates are cheaper than the conventional carbon sources and are, as well, more readily available.

Keywords

• Culture conditions
• Maize stover
• Peroxidase
• Sawdust
• Submerged fermentation
• Wheat straw