Author:
Han Bei,Ujor Victor,Lai Lien B.,Gopalan Venkat,Ezeji Thaddeus Chukwuemeka
Abstract
ABSTRACTCalcium carbonate increases growth, substrate utilization, and acetone-butanol-ethanol (ABE) fermentation byClostridium beijerinckiiNCIMB 8052. Toward an understanding of the basis for these pleiotropic effects, we profiled changes in theC. beijerinckiiNCIMB 8052 proteome that occur in response to the addition of CaCO3. We observed increases in the levels of different heat shock proteins (GrpE and DnaK), sugar transporters, and proteins involved in DNA synthesis, repair, recombination, and replication. We also noted significant decreases in the levels of proteins involved in metabolism, nucleic acid stabilization, sporulation, oxidative and antibiotic stress responses, and signal transduction. We determined that CaCO3enhances ABE fermentation due to both its buffering effects and its ability to influence key cellular processes, such as sugar transport, butanol tolerance, and solventogenesis. Moreover, activity assaysin vitrofor select solventogenic enzymes revealed that part of the underpinning for the CaCO3-mediated increase in the level of ABE fermentation stems from the enhanced activity of these catalysts in the presence of Ca2+. Collectively, these proteomic and biochemical studies provide new insights into the multifactorial basis for the stimulation of ABE fermentation and butanol tolerance in the presence of CaCO3.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
63 articles.
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