Isolation of free-living dinitrogen-fixing bacteria and their activity in compost containing de-inking paper sludge.
Knowledge of the microbiology of dinitrogen (N2)-fixing bacteria in compost rich in de-inking paper sludge (DPS) is limited. Dinitrogen (N2)-fixing bacteria from DPS composts were isolated and studied for their N2-fixing activity in vitro and in vivo. Two Gram-negative N2-fixing isolates were identified as Pseudomonas. At 20 degrees C, both isolates revealed that N2-fixing activity was higher than that of three arctic Pseudomonas strains. Their N2-fixing activity was found to occur between 18 and 25 degrees C, a pattern that was similar to the reference isolate Azotobacter ATCC 7486. Composts successfully showed N2-fixing activity after carbohydrate amendments both with and without inoculation of a N2-fixing isolate. These results suggest that DPS composts support N2-fixing bacteria and that N2-fixing activity is dependent on a usable carbohydrate source.
Beauchamp
Chantal J
CJ
Département de phytologie, Université Laval, Sainte-Foy, Québec, Canada G1K 7P4. chantal.beauchamp@plg.ulaval.ca
Lévesque
Gabriel
G
Prévost
Danielle
D
Chalifour
François-P
FP
D001395:Azotobacter / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D007281:Ink; D009584:Nitrogen / Q000378:metabolism; D009586:Nitrogen Fixation; D010209:Paper; D011549:Pseudomonas / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D012015:Reference Standards; D012722:Sewage; D012987:Soil; D013696:Temperature
D012722:Sewage; D012987:Soil; D009584:Nitrogen