Quimica

Claude E. Zobell: Pioneer Microbial Ecologist

ZoBell’s contribution to petroleum microbiology
Catherine Bass
Environmental Microbiology Research Group, Hatherly Laboratories, University of Exeter, EX4 4PS UK

ABSTRACT Claude ZoBell’s recognition of the influence of microorganisms in the ecology of petroleum bearing environments was all encompassing. This translated into a uniquecontribution over the entire span of the oil industry. Many of his publications in the 1940s and 1950s discussed the key role of microorganisms in the diagenesis of hydrocarbon products. At a time when the industry was treating the supply of crude oil as an almost inexhaustible reserve, ZoBell’s thoughts were turning to improved oil recovery using bacterial products such as acids and gases to aidmobilisation and he also recognised the inevitable problems of oil spill pollution and the potential for use of bacteria as control agents. In all areas of the oil industry today there is an increasingly clear recognition of the influence of associated microflora. Perhaps if there had been wider recognition of Claude ZoBell’s work throughout the middle decades of this century more microbially mediatedimproved oil recovery and bioremediation treatments would be in place today. Introduction There have been few microbiologists with as wide a knowledge of the petroleum industry as Claude ZoBell, with both a clear understanding of the influence of bacteria in the ecology of oil reservoirs and also a well developed sense of the value of harnessing the activities of those same bacteria to improve oilrecovery, or modify the product. He was a member of both the American Petroleum Institute (API) and the American Association of Petroleum Geologists (AAPG) as well as maintaining long term consultative associations with major oil companies such as Texaco Development Corporation (ten years) and Exxon Research (fifteen years). Petroleum microbiology can be divided into six broad areas, starting withdiagenesis of organic components in sediments and subsequent oleogenesis, degradation of hydrocarbons, improved recovery of hydrocarbons from reservoirs, modification of hydrocarbon products either in the formation or post production, mitigation of the effects of ‘nuisance organisms’ during production and bioremediation of escaped product either crude or processed. Claude ZoBell worked in most ofthese areas, documented in his output of 66 papers between 1938 and 1978 (of a total 248), and related to one or other of these aspects of petroleum microbiology. His legacy is an unique contribution to the oil industry which is still consulted today, offering source material in many diverse areas of the petroleum industry and also for the growing community of subsurface microbiologists.

MicrobialBiosystems: New Frontiers Proceedings of the 8th International Symposium on Microbial Ecology Bell CR, Brylinsky M, Johnson-Green P (ed) Atlantic Canada Society for Microbial Ecology, Halifax, Canada, 1999.

Claude E. Zobell: Pioneer Microbial Ecologist

Part played by bacteria in petroleum formation Following ZoBell’s appointment at Scripps Institute of Oceanography (SIO) in 1932 heconcentrated on the study of marine bacteria [1, 2] and their role in the transformations of organic material in sediments [3, 4]. The 1938 publication [3] was important in that it described the existence of a rich microflora inhabiting ocean bottom deposits, samples having been taken using a modified Ekman coring device which ensured uncontaminated samples of sediment. ZoBell was able to disprove theassertions of what he termed the ‘popular literature’, that high hydrostatic pressure and low temperature are inimical to the existence and activity of bacteria. In particular he highlighted the activities of bacteria cultured from the sediments whose ‘biochemical activities may geologically modify their environment’. In 1941 he presented a report on the origins of oil at a meeting of the AAPG in...