Production of a cellulose-aminating polysaccharide from a filamentous sulfur-oxidizing bacterium, <i>Thiothrix nivea</i>, grown lithotrophically or mixotrophically

Thiothrix nivea was cultured, and glucosaminoglucan was produced lithotrophically using Na2S for feeding. Na2S is also indispensable for mixotrophic growth and glucosaminoglucan production, indicating that sulfide oxidation pathways control the TCA cycle. The involvement of the SOX pathway (for thiosulfate oxidation) in the activation of energy metabolism is doubtful because neither lithotrophic nor mixotrophic growth was promoted by Na2S2O3. Based on these results, we assumed that T. nivea is facultatively mixotrophic [lithotrophic growth is possible in addition to organotrophic growth in the presence of sulfide (Na2S)], rather than obligately mixotrophic.