Exoproduction and Molecular Characterization of Peroxidase from Ensifer adhaerens

Abstract

The increased industrial application potentials of peroxidase have led to high market demand, which has outweighed the commercially available peroxidases. Hence, the need for alternative and efficient peroxidase-producers is imperative. This study reported the process parameters for enhanced exoperoxidase production by Ensifer adhaerens NWODO-2 (accession number: KX640918) for the first time, and characterized the enzyme using molecular methods. Peroxidase production by the bacteria was optimal at 48 h, with specific productivity of 12.76 U mg−1 at pH 7, 30 °C and 100 rpm in an alkali lignin fermentation medium supplemented with guaiacol as the most effective inducer and ammonium sulphate as the best inorganic nitrogen source. Upon assessment of some agricultural residues as sources of carbon for the enzyme production, sawdust gave the highest peroxidase productivity (37.50 U mg−1) under solid-state fermentation. A search of the polymerase chain reaction (PCR)-amplified peroxidase gene in UniProtKB using blastx showed 70.5% similarity to an uncharacterized protein in Ensifer adhaerens but phylogenetic analysis suggests that the gene may encode a catalase-peroxidase with an estimated molecular weight of approximately 31 kDa and isoelectric point of about 11. The nucleotide sequence of the detected gene was deposited in the GenBank under the accession number MF374336. In conclusion, the ability of the strain to utilize lignocellulosic materials for peroxidase production augurs well for biotechnological application as this would greatly reduce cost, which is a major challenge in industrial enzyme production.

Studies on peroxidase production and detection of Sporotrichum thermophile-like catalase-peroxidase gene in a Bacillus species isolated from Hogsback forest reserve, South Africa

“…FALADE-1 (LGO: 3.15 U mL −1 , LG + GA: 6.42 U mL −1 ), repressed peroxidase activity in the studied bacteria. This result is comparable to a recent study (Falade et al., 2019c), in which guaiacol supported maximum peroxidase secretion by E. adhaerens while vanillin, vanillic and ferulic acids repressed peroxidase production in the study. This is also corroborated by Falade et al.…”

“…In contrast, Patil (2014) reported 180 rpm as the optimal for peroxidase secretion by a Bacillus species . Moreover, Falade et al. (2019c) observed 100 rpm as the optimal agitation speed for peroxidase production by Ensifer adhaerens NWODO-2 .…”

“…In this case, optimum peroxidase production may be attributed to increased aeration of the cultivation medium, consequently, supplying adequate dissolved oxygen in the medium (Kumar and Takagi, 1999; Sepahy and Jabalameli, 2011) as well as increased nutrient uptake by the bacteria (Sepahy and Jabalameli, 2011; Beg et al., 2003). The decrease observed in peroxidase production at agitation rate higher than 150 rpm, may be due to foaming and shearing effects (Falade et al., 2019c) as high agitation may result in cell damage, consequently reducing the number of peroxidase producers. This finding is in agreement with our recent study (Falade et al., 2019b), where optimum exoperoxidase activity by Raoultella ornithinolytica OKOH-1 was observed at 150 rpm.…”

“…Some lignin monomers have been implicated in the induction of peroxidase production by bacteria (Falade et al. 2019b; c). In this study, the fermentation medium was augmented with 1 mmol L −1 of the various lignin monomers (guaiacol-GA, veratryl alcohol-VALC, vanillin-VAL, vanillic acid-VA and ferulic acid-FA) and the results are shown in Figure 4.…”

“…The effects of nitrogen on the secretion of ligninolytic enzymes have been widely studied (Kachlishvili et al., 2005; Mikiashvili et al., 2006; Stajić et al., 2006; Falade et al., 2019b, c). However, only limited studies are available on the impacts of nature and concentration of nitrogen sources on production of peroxidase.…”