ISOLATION AND IDENTIFICATION OF NON-SYMBIOTIC NITROGEN-FIXING BACTERIA IN PRANCAK VILLAGE TOBACCO FARMING SOIL

The Prancak 95 tobacco plant is one of the best tobaccos in Indonesia; it comes from Prancak Village. The biggest nutrient needed in the growth of tobacco is nitrogen. Nitrogen in the atmosphere is very abundant, but it cannot be used directly by plants. The availability of nitrogen, one of which can be fulfilled by the presence of non-symbiotic nitrogen-fixing bacteria (NFB), The study's goal was to isolate non-symbiotic NFB from tobacco farming soil in Prancak 95 so that the population, potential, and genus of these bacteria that can fix nitrogen could be found. The samples used were Prancak 95 tobacco farms in Tegal Barat and Bilamabuk hamlets. Isolated non-symbiotic NFB were grown on Yeast Extract Mannitol Agar (YEMA) media by the pour plate method and incubated for 3 days at 37ºC. Pure isolates were identified macroscopically, microscopically, and biochemically based on Bergey's Manual of Determinatives and measured the potential of bacteria as non-symbiotic NFB based on the ratio of clear zones on YEMA media with the addition of Congo red. The results of this study showed that the average non-symbiotic NFB population in Tegal Barat Hamlet was 3,25 x 105 cfu/ml, while in Bilamabuk Hamlet it was 2,7 x 105 cfu/gr, and 6 bacterial isolates were selected for further research. All selected isolates have the potential to be non-symbiotic NFB, with clear zone ratios ranging from 1,26-2,60 cm. Based on the results of the characterization and identification of non-symbiotic NFB bacterial isolates with the codes PT2, PB1, and PB3, they tend to lead to the bacterial genus Bacillus sp., while PT1, PT3, and PB2 tend to lead to the 21 bacterial genus Corynebacterium sp.