Isolation and evaluation of chlorogenate hydrolase producing fungi

Abstract

Chlorogenate hydrolase catalyzes the hydrolysis of chlorogenic acid, releasing caffeic and quinic acids. This enzyme can be used to extract caffeic acid from agro-industrial byproducts (apple marc, coffee pulp, brewer's spent grain, among others), and to synthesize caffeic acid derivatives. This work aimed to isolate and identify fungal strains capable of producing enzymes with chlorogenate hydrolase activity. Twelve fungal strains were isolated from fresh coffee cherries, dry coffee cherries, and green coffee beans. The isolated fungi were analyzed for their morphology and ability to assimilate chlorogenic acid. Four fungal isolates were identified as Aspergillus sp., two as Fusarium sp., and one as Cladosporium sp. All the fungal isolates were able to grow using chlorogenic acid as the sole carbon source. The CR1 strain, identified as Aspergillus niger by sequencing of the ITS region, was selected due to its high radial growth rate (0.27 ± 0.01 mm h^-1). This strain grew and showed chlorogenate hydrolase activity in Submerged (SmF) and Solid-State Fermentation (SSF). The maximum chlorogenate hydrolase activity in SSF (34.6 ± 11.8 U/L) was 2.1-fold higher than in SmF (16.2 ± 1.6 U/L). These results provide the basis for developing applications based on the use of enzymes with chlorogenate hydrolase activity.