ABSTRACT
Historically, probiotics not only have been used to serve as biological mixtures of microorganisms for potential promotion of health benets in humans and animals but have also been used extensively to limit the colonization of foodborne pathogens particularly in food animals, sh, and poultry (Nisbet, 2002; Burr et al., 2005; Chaucheyras-Durand and Durand, 2010; Hanning et al., 2010; Hume, 2011; Callaway and Ricke, 2012; Siragusa and Ricke, 2012; O’Bryan et al., 2013). In general, much of the research over the past few decades has focused on using probiotics also referred to as competitive exclusion products or direct fed microbials to limit foodborne pathogen establishment in food animals (Mead, 2000; Nisbet, 2002; Patterson and Burkholder, 2003; Hume, 2011; Siragusa and Ricke, 2012; Ricke et al., 2013b). Initial consistent success was achieved using continuous culture-generated mixtures of cecal competitive exclusion cultures to limit the establishment of Salmonella in young chickens (Nisbet et al., 1994, 1996a,b). The early establishment of a protective microora in the host’s gastrointestinal tract is believed to elicit several antagonistic mechanisms against foodborne pathogens, Salmonella and Campylobacter, including the generation of antimicrobial compounds such as short-chain fatty acids (SCFAs) and bacteriocins, competition for limiting nutrients, competition for binding sites in the gastrointestinal tract, as
19.1 Introduction ...................................................................................................................................341 19.2 Bacillus: Application as a Probiotic Culture................................................................................ 342 19.3 Bacillus spp. as an Insecticide and Development of Transgenic Plants ...................................... 344 19.4 Bacillus as a Source of Enzymes ................................................................................................. 346 19.5 Bacillus spp. and Potential for Heterologous Protein Production ............................................... 347
19.5.1 Advantages of Bacillus spp. as Protein Expression Organisms ...................................... 347 19.5.2 Problematic Issue of Extracellular Proteases .................................................................. 348
19.5.2.1 B. subtilis ......................................................................................................... 348 19.5.2.2 Brevibacillus choshinensis .............................................................................. 348 19.5.2.3 B. megaterium .................................................................................................. 348
19.5.3 Protein Expression Systems for Bacillus ......................................................................... 349 19.5.3.1 Spac Promoter .................................................................................................. 349 19.5.3.2 Xylose-Inducible Promoter .............................................................................. 349
19.5.4 Secretion Systems of Bacillus ......................................................................................... 350 19.5.5 Propeptides .......................................................................................................................351
