Optimization of bacterial bioaugmentation for groundwater Mn removal using a waste-based culture medium and lyophilization

Abstract

Waste based bacterial culture media and inoculum lyophilization to optimize bioaugmentation processes applicable to Mn groundwater full-scale biofiltration.

C-di-GMP signalling links biofilm formation and Mn(II) oxidation in Pseudomonas resinovorans

“…Sand inoculated with MOB-513-pBdcB fresh cultures or lyophiles, both grown in Lept or Lept-Mn, showed a higher Mn(II) oxidation capacity than those inoculated with MOB-513-pEmpty (Table 2). On the other hand, and as previously observed (10), bacterial adaptation to Mn(II) performed by growing the strains in Lept-Mn enhanced the oxidation of Mn(II) present in groundwater (Table 2). No BMnOx was detected for MOB-513-pBpdeA at the assayed timepoints (Table 2).…”

“…Previous studies showed the usefulness of MOB lyophilised cultures to replace large volumes of inoculum and to enhance groundwater Mn removal performance (10). Since MOB-513-pBdcB shows a higher biofilm formation capacity and is a hyper-oxidant bacterial strain, we expanded our analysis to consider the biotechnological relevance of c-di-GMP function in MOB-513.…”

“…MOB-513 strains were lyophilized following as previously described (10). Viability of bacteria (CFU/mL) before and after lyophilisation was used to calculate the cell survival rates (SR) as follow:…”

“…The biofilm-forming capability of bacteria is important to achieve the optimal filtration of groundwater for metals, as they have to be oxidized and retained into the biofilter matrix surface, and to decrease the loss of the MOBs, which can otherwise be washed out of the system (4,5,8). It has been recently shown that powdered MOB inoculates prepared by vacuum lyophilisation are useful to inoculate sand filters and remove Mn with high efficiencies (10). Moreover, lyophilisation efficiencies increase when MOB are grown under biofilms instead of shaking culture conditions (10), demonstrating that an understanding of biofilm formation in MOBs may help to implement these bacteria in biotechnological applications.…”

“…It has been recently shown that powdered MOB inoculates prepared by vacuum lyophilisation are useful to inoculate sand filters and remove Mn with high efficiencies (10). Moreover, lyophilisation efficiencies increase when MOB are grown under biofilms instead of shaking culture conditions (10), demonstrating that an understanding of biofilm formation in MOBs may help to implement these bacteria in biotechnological applications.…”