 BOSTON--BUSINESS WIRE--Advent Technologies Holdings, Inc. NASDAQ: ADN Advent today announced that it has entered into a definitive agreement to acquire the fuel cell systems businesses of fischer Group for an aggregate consideration of cash and stock of EUR52 million. These businesses include Serenergy AS, SerEnergy based in Aalborg, Denmark, and fischer eco solutions GmbH, FES based in Achern, Germany. SerEnergy is a leading manufacturer of high-temperature polymer electrolyte 