Novel Strategies for Overproduction of Microbial Products

摘要

Biotechnology and pharmaceutical industries are in continual quest for the discovery of novel products and the enhancement of productivity of value products to retain their global competitiveness. Traditional methods employed to achieve these goals include microbial strain selection, culture improvement, media development, and, bioreactor and process design. These methods, however, suffer from severe drawbacks such as the long time required for successful outcomes, high expenses and, in many cases, low success rate. Over the last fifteen years we have introduced two novel strategies for overproduction of industrially desirable microbial products. These strategies are based on microbial response to the microbes in their vicinity (quorum sensing) and, to their surrounding environment (elicitation). In all these cases, enhancement of productivity was established with several fold increases: in the elicitation work, addition of oligosaccharide (oligomannuronate and oligoguluronate blocks) resulted in a 50% increase in penicillin G yield for Penicillium chrysogenum. While Bacillus licheniformis cultures supplemented with oligoguluronate resulted in over 19% and 11% increase in bacitracin A yield in the shaken flasks and bioreactors respectively. In quorum sensing studies addition of spent medium from Penicillium sclerotiorum IMI 104602 (strain M) - a high producer of multicolic acid- to P. sclerotiorum IMI 040574 strain S) - a low producer of multicolic acid- led to a 6.4- fold increase in sclerotiorin yield. We suggest that exploitation of microbes' communications to other microbes (selfcommunity) and to the environment may provide new industrial opportunities for improved productivity of microbial biomolecules.