Biomorphic Mg-Al layered double hydroxides (LDHs) templated from pine sawdust as precursors, hierarchically structured Mg-Al mixed metal oxides (MMOs) with well-developed porosity were prepared through biological template method and hydrothermal process. As-synthesized composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and nitrogen adsorption measurements. Adsorption conditions including different Congo red concentration, contact time, pH and temperature were investigated. Antibacterial ability and mechanism against Escherichia coli and Staphylococcus aureus were analyzed. MMOs exhibited higher adsorption and stronger antibacterial ability as compared with biomorphic LDHs. The concept provides new insight into design and preparation efficient adsorption and antibacterial materials.