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Accumulation
Published in Joel L. Plawsky, Transport Phenomena Fundamentals, 2020
Let's look at the particular situation shown in Figure 6.33. Assume we have a tube filled with growth medium. The tube is of cross-sectional area, Ac, and radius, r0, and is much longer that it is wide. At the center we inoculate it with a strain of non-motile bacteria. Within a short period of time, the bacteria grow in all directions until they span the radial dimension of the tube. Thereafter, they can only spread down the axis of the tube and appear to do so at a constant velocity. We assume the bacteria are moving via diffusion only, since they are non-motile. If there is enough food and space, the bacteria numbers increase exponentially with time. Exponential growth is equivalent to a first-order chemical reaction. If we take a small slice in the axial direction, we can write a balance equation for the bacterial population.
Enzyme Catalysis
Published in Harvey W. Blanch, Douglas S. Clark, Biochemical Engineering, 1997
Harvey W. Blanch, Douglas S. Clark
It is thought that chemotaxis and motility may provide some survival advantages over non-motile bacteria. Some studies have shown that chemotatic bacteria grown in quiescent media or on semi-solid agar indeed show higher rates of growth than non-motile strains.
Algicidal bacteria against cyanobacteria: Practical knowledge from laboratory to application
Published in Critical Reviews in Environmental Science and Technology, 2023
Jesús Morón-López, Liliana Serwecińska, Łucja Balcerzak, Sława Glińska, Joanna Mankiewicz-Boczek
The bacterium Chryseobacterium ureilyticum also exerted the highest algicidal effect against diazotrophic filamentous cyanobacteria (Figure 4). This trend has been observed here for the first time, as the two previous studies focused on Microcystis spp. (Guo et al., 2015; C. Zhang et al., 2019). It has been suggested that some members of this genus also perform simultaneous heterotrophic nitrification and aerobic denitrification (Kundu et al., 2014); hence, this raises the question of whether there could be any relationship between this metabolic capability and the higher sensitivity shown by the N2-fixing cyanobacteria. The genus Chryseobacterium (Flavobacteriales, Bacteroidetes) includes aerobic, Gram negative, nonspore-forming rods without flagellar motility (i.e., atrichous type, Figure 3E). It is remarkable that studies with M. aeruginosa colonies found that non-motile bacteria, such as Chryseobacterium spp., significantly increased colony size, while flagellated bacterial species, such as Bacillus, Exiguobacterium and Stenotrophomonas, decreased it (Gumbo et al., 2010; W. Wang et al., 2016; Q. Wu et al., 2019). One could speculate that, following a random encounter of a non-motile Chryseobacterium spp. cell (see Figure 2), it induces the production of extracellular polysaccharides in M. aeruginosa to enhance colony formation and cell stickiness (Le et al., 2022; Wichelen et al., 2016), and thus achieving a close spatial coupling. In contrast, the flagellated species of Bacillus, Exiguobacterium and Stenotrophomonas are challenged to reach individual cells which are interlocked within the colony, and therefore they promote the reduction of the colony size and separation to lessen its protective capacity (Gumbo et al., 2010; X. Wang et al., 2013).