In situ bacterial mitigation of the toxic cyanobacterium Microcystis aeruginosa: implications for biological bloom control

Abstract

The algicidal bacterium Xanthobacter autotrophicus HYS0201-SM02 (SM02) was isolated from the surface water of a eutrophic lake (Lake Daechung, Korea). In vivo and in situ experiments showed that SM02 had algicidal activity against both a cultured strain and natural colonial morphs of the toxic cyanobacterium, Microcystis aeruginosa. Both the SM02 bacteria and its culture filtrate showed anti-algal activity against M. aeruginosa, indicating that an algicidal substance was released from SM02. The threshold concentration of SM02 for maximal algicidal activity against a natural bloom of M. aeruginosa was 10 7 CFU/mL. In situ co-culture of SM02 and M. aeruginosa showed that SM02 did not benefit from the massive decay of M. aeruginosa. In fact, repeated inoculations with a low concentration of SM02 were required for optimal algicidal activity, suggesting that water quality worsened during co-culture (i.e., nutrients and microcystin-LR concentration increased). These results suggest a role for the algicidal bacterium X. autotrophicus SM02 in biorestoration but probably not in treating outdoor Microcystis blooms. When developing a biological agent to control M. aeruginosa blooms in the field, it will be important to screen for specific agents with low threshold concentrations and high algicidal activity.

Pseudomonas aeruginosa UCBPP-PA14 a useful bacterium capable of lysing Microcystis aeruginosa cells and degrading microcystins

“…In contrast, generalists, such as the bacteria Variovorax paradoxus SK12 and Pseudomonas plecoglossicida PK05 isolated by Kang et al (2008), have the excellent ability to survive due to a broad range of alternative prey, given a low abundance of their primary prey and the applicable possibility to control various algal species. However, generalists have raised some concern with regard to host switching and host range expansion, resulting in disruption of biological control (Koss and Snyder 2005;Kim et al 2008;Gumbo et al 2010). Thus, our results suggest that the proper inoculation of initial bacterial density is necessary to achieve species-specific control without undesired consequences because higher initial inoculation may interfere with biological control and environmental safety by killing other algae species or organisms.…”

The algicidal activity of Aeromonas sp. strain GLY‐2107 against bloom‐forming Microcystis aeruginosa is regulated by N‐acyl homoserine lactone‐mediated quorum sensing

“…Algicidal bacteria have been found to play an important role in the regulation and termination of blooms in some lakes (Rashidan and Bird, ; Zhang et al ., ). Furthermore, algicidal bacteria and the corresponding algicidal substances have been shown to be effective for the control of harmful cyanobacteria (Manage et al ., ; Kim et al ., ; Li et al ., ; Lin et al ., ).…”

Algicidal Activity of a Dibenzofuran-Degrader Rhodococcus sp.

“…To date, algicidal bacteria belonging to different genera have been isolated, including Aquimarina salinaria [4], Alteromonas sp. [6], Xanthobacter autotrophicus [14], Acidovorax delafieldii [13], Sinorhizobium kostiense [16], Bacillus [21], Dietzia, Janibacter, Micrococcus [18], and so on. Although studies have shown phylogenetic relations of some algicidal strains [14], it seems that the algicidal bacteria are naturally widespread and taxonomically diversified.…”

“…[6], Xanthobacter autotrophicus [14], Acidovorax delafieldii [13], Sinorhizobium kostiense [16], Bacillus [21], Dietzia, Janibacter, Micrococcus [18], and so on. Although studies have shown phylogenetic relations of some algicidal strains [14], it seems that the algicidal bacteria are naturally widespread and taxonomically diversified. Screening for algicidal bacteria in natural water bodies has displayed an abundance of natural bioagent resource [13,30].…”