Characterization of pectin lyase produced by an endophytic strain isolated from coffee cherries

Abstract

The effect of endophytic bacterial activity on the quality of coffee beverage was studied. A survey of the micro-organisms in coffee cherries was performed before harvesting, and their growth on the main nutrients available in coffee cherries was determined in vitro. Many endophytic bacteria were isolated from surface-sterilized coffee cherries. One of the pectinolytic strains was physiologically and phenotypically characterized, and was tentatively identified by partial 16S rDNA sequencing as Paenibacillus amylolyticus. This endophytic strain produced an extracellular pectinase with maximal activity at 40°C and pH 7·9, and was thermostable up to 45°C. EDTA and metal ions had little effect on pectin lyase activity. Km and Vmax values were 4·6 mg ml–1 and 94·0 10–8 mol min–1 ml–1, respectively. Pectin lyases have been found in fungi but rarely in bacteria, and this isolate is a promising tool for regulation studies of these enzymes.