Increasing the scale of peroxidase production by Streptomyces sp. strain BSII#1

Abstract

AIMS : To optimise peroxidase production by Streptomyces sp. strain BSII#1, up to 3 l culture volumes. METHODS AND RESULTS : Peroxidase production by Streptomyces sp. strain BSII#1 was optimised in terms of production temperature and pH and the use of lignin-based model chemical inducers. The highest peroxidase activity (1.30±0.04 U ml-1) in 10 ml culture volume was achieved in a complex production medium (pH 8) at 37°C in the presence of 0.1 mmol l-1 veratryl alcohol, which was greater than those reported previously. Scale-up to 100 ml and 400 ml culture volumes resulted in decreased peroxidase production (0.53±0.10 U ml- 1 and 0.26±0.08 U ml-1 respectively). However, increased aeration improved peroxidase production with the highest production achieved using an airlift bioreactor (4.76±0.46 U ml-1 in 3 l culture volume). CONCLUSIONS : Veratryl alcohol (0.1 mmol l-1) is an effective inducer of peroxidase production by Streptomyces sp. strain BSII#1. However, improved aeration increased peroxidase production in larger volumes without the use of an inducer, surpassing induced yields in an optimised small-scale process. SIGNIFICANCE AND IMPACT OF THE STUDY : Only a limited number of reports in literature have focused on the up-scaling of bacterial peroxidase production. There remains opportunity for feasible large-scale production of bacterial peroxidases with potentially novel biocatalytic properties.