Ralph Mitchell

Ralph Mitchell

  • Gordon McKay Professor of Applied Biology, Emeritus


In recent years the field of microbiology has made dramatic advances. New tools and methods are being employed to investigate fundamental microbial processes, and new biotechnological techniques are being used to induce microorganisms to produce an extraordinary range of pharmaceutical, agricultural, and industrial substances. Professor Mitchell's laboratory is engaged in research on microbial processes in natural habitats and in applied microbiology, on subjects that include control of the deterioration of materials by microorganisms and the development of targeted pesticides.

Professor Mitchell's laboratory is currently involved in extensive research on the ability of microbes to attack nonliving materials, including metals, concrete, stone and artificial polymers. His research has shown that materials used in electronics, on buildings, and in industrial processes are susceptible to microbial "diseases."

Professor Mitchell's group is particularly interested in the association between increased pollution and the acceleration in recent years in the biodeterioration of ancient buildings and monuments. One current project involves a study of the role of microorganisms in the accelerated deterioration of historic limestone by atmospheric pollutants. In another investigation, his research group is investigating the biodeterioration of consolidants used to protect archeological sites, with the goal of developing environmentally acceptable binding materials for historic buildings, which are capable of resisting biodegradation.

A major project of the Mitchell laboratory concerns the microbiology of surfaces. Studies of the complex chemical and biochemical interactions that occur at the interface between an aqueous phase and a living or nonliving surface provide insight into the chemical transformations mediated by microorganisms found on the surfaces of both living and artificial materials. Professor Mitchell's group has identified biochemical cues produced by surface-active bacteria that induce the development of invertebrate organisms. Their observations help explain how developing organisms use external biochemical triggers and provide new means for controlling undesirable insects and other pests.

Contact Information

Office:Pierce 100E
Office Phone:(617) 496-3906
Office Fax(617) 496-1471
Lab Name:Laboratory of Applied Microbiology
Lab Location:301 Engineering Sciences Lab
Lab Phone:(617) 496-3906
Assistant:Julianna Braun
Assistant Office:29 Oxford Street 118
Assistant Phone:(617) 495-0627

Primary Teaching Area

Positions & Employment

Harvard School of Engineering and Applied Sciences

  • Present: Gordon McKay Research Professor of Applied Biology