Separation and purification of pyrroloquinoline quinone from fermentation broth by pretreatment coupled with macroporous resin adsorption

Abstract

Pyrroloquinoline quinone (PQQ) is widely found in fruits and vegetables and in human breast milk; it is considered a ‘longevity vitamin’ and is used as a functional food. In this study, a two-step process for the large-scale separation and purification of PQQ from the crude fermentation broth of a methylotrophic bacterium was developed. Pretreatment was accomplished by centrifugation and filtration (Process I), and then macroporous resins were applied for further purification (Process II). On the basis of static adsorption/desorption tests and the well-described pseudo-first order kinetic model, XAD-1600 was chosen as the most suitable resin for PQQ separation. The equilibrium adsorption data were well fitted to both the Langmuir and Freundlich isotherms, and dynamic adsorption/desorption tests were performed to standardize the operational parameters for a scaled-up PQQ purification procedure. Finally, the recovery yield of PQQ with 96.23% purity after pretreatment and macroporous resin treatment reached 82.57%, and 93.62 g PQQ crystals with over 99% purity were obtained from 70 L of crude fermentation broth (1.674 g/L PQQ). Thus, our strategy for the large-scale separation and purification of PQQ from fermentation broth might be beneficial for meeting the increasing demand for PQQ in the food and pharmaceutical industries.