Thuy Thi Tran Doctoral Thesis 2010 Department of Biotechnology Lund University Printed by Media-Tryck, Sweden ISBN 978-91-89627-67-3 Thuy Thi Tran Thermostable phytase from a Bacillus sp. 2010 Thermostable phytase from a Bacillus sp. Heterologous production, mutation, characterization and assay development