A valuable peroxidase activity from the novel species Nonomuraea gerenzanensis growing on alkali lignin

Carmine Casciello; Fabio Tonin; Francesca Berini; Elisa Fasoli; Flavia Marinelli; Loredano Pollegioni; Elena Rosini

doi:10.1016/j.btre.2016.12.005

A valuable peroxidase activity from the novel species Nonomuraea gerenzanensis growing on alkali lignin

Biotechnol Rep (Amst). 2017 Jan 3:13:49-57. doi: 10.1016/j.btre.2016.12.005. eCollection 2017 Mar.

Authors

Carmine Casciello¹, Fabio Tonin¹, Francesca Berini¹, Elisa Fasoli², Flavia Marinelli¹, Loredano Pollegioni¹, Elena Rosini¹

Affiliations

¹ Department of Biotechnology and Life Sciences, University of Insubria, via J.H. Dunant 3, 21100 Varese, Italy; The Protein Factory Research Center, Politecnico of Milano and University of Insubria, via Mancinelli 7, 20131 Milano, Italy.
² Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico of Milano, via Mancinelli 7, 20131, Milano, Italy.

Abstract

Degradation of lignin constitutes a key step in processing biomass to become useful monomers but it remains challenging. Compared to fungi, bacteria are much less characterized with respect to their lignin metabolism, although it is reported that many soil bacteria, especially actinomycetes, attack and solubilize lignin. In this work, we screened 43 filamentous actinomycetes by assaying their activity on chemically different substrates including a soluble and semi-degraded lignin derivative (known as alkali lignin or Kraft lignin), and we discovered a novel and valuable peroxidase activity produced by the recently classified actinomycete Nonomuraea gerenzanensis. Compared to known fungal manganese and versatile peroxidases, the stability of N. gerenzanensis peroxidase activity at alkaline pHs and its thermostability are significantly higher. From a kinetic point of view, N. gerenzanensis peroxidase activity shows a K_m for H₂O₂ similar to that of Phanerochaete chrysosporium and Bjerkandera enzymes and a lower affinity for Mn²⁺, whereas it differs from the six Pleurotus ostreatus manganese peroxidase isoenzymes described in the literature. Additionally, N. gerenzanensis peroxidase shows a remarkable dye-decolorizing activity that expands its substrate range and paves the way for an industrial use of this enzyme. These results confirm that by exploring new bacterial diversity, we may be able to discover and exploit alternative biological tools putatively involved in lignin modification and degradation.

Keywords: 2,4-DCP, 2,4-dichlorophenol; 2,6-DMP, 2,6-dimethoxyphenol; ABTS, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid); Alkali lignin; DyP, dye decolorizing peroxidase; Filamentous actinomycetes; Kraft lignin; LiP, lignin peroxidase; MAM, mannitol agar medium; MM-L, minimal salt medium plus lignin; MnP, manganese peroxidase; Nonomuraea gerenzanensis; Peroxidases; RB5, reactive black 5; RBBR, remazol brilliant blue R; VP, versatile peroxidase.