Microfouling of manganese-oxidizing bacteria in Tuticorin harbour waters

Abstract

Implication of manganese-oxidizers in corrosion of
\nvarious alloys stimulated the investigators to concentrate
\non these aspects. In the present study, an attempt
\nwas made to bring out the bacterial genera involved in
\nthe oxidation of manganese in biofilms. The materials
\nimmersed in sea water for biofilm formation included
\npolyvinyl chloride (PVC), stainless steel (SS), brass
\nand copper. The biofilm samples were analysed quantitatively
\nand qualitatively for both heterotrophic
\nbacterial population (HB) and manganese-oxidizing
\nheterotrophic bacterial population (MHB). Both qualitative
\nand quantitative examination of biofilms showed
\nrelatively poor population density on copper. Qualitative
\nexamination revealed the representation of
\nboth Gram-positive and Gram-negative bacteria on
\nall materials. However, only Gram-positive groups,
\nespecially of the endospore-forming genus Bacillus
\nand non-endospore forming genus Propionibacterium
\nwere observed on copper coupons. Gram-positive
\ngenera dominated over Gram-negative genera in most
\nof the biofilms studied. The genera identified under
\nmanganese-oxidizing bacterial isolates were Bacillus,
\nStaphylococcus, Synecoccus, Propionibacterium, Micrococcus,
\nPseudomonas and Vibrio. Among them, Bacillus
\nspecies was most commonly encountered in all the
\nmaterials studied. Potential measurements for SS316
\nshowed positive shift. Analysis revealed enormous
\namount of manganese in the biofilms.