Isolation and characterization of resistance traits of indigenous strains ofAcetobacter diazotrophicus associated with sugarcane
2004
Aḥmad, Iqbāl | Sharma, Jyoti | Ahmed, Farah
A total of 11 strainsof Acetobacter diazotrophicus were isolated from roots, leaves and stems of the four locally grown cultivars of sugarcane (Co-1148, UP 39, Satha-676, Satha-91269) of Aligarh. These strains and three Brazilian strains ofAcetobacter diazotrophicus (PR2-ATCC49039, PaI5-ATCC. 49037, Ppe-4 ATCC49038) were studied for their biochemical characteristics and resistance traits. All isolated strains exhibited similar cultural and biochemical characteristics to that of reference strains. These strains utilized sucrose, glucose and 1% ethanol while no strain could utilize maltose and 10% ethanol. Fructose was utilized differentially; similarly all strains were positive for catalase, H₂S production and negative for oxidase, NO₃ reduction, denitrification, gelatin liquefaction and indole test. Antibiotic resistance in theAcetobacter diazotrophicus was exhibited by 12 out of 14 strains. Similarly, metal resistance at MIC. 100 μg/ml was found maximum against Pb followed by Cd, Hg, Ni and Cu. Most of the indigenous strains showed resistance to both antibiotics and heavy metals. However, three Brazilian strains ofAcetobacter diazotrophicus were sensitive to all metals tested. Similarly tolerance to salt (NaCl) was higher 1.0% to 1.5% among indigenous strains as compared to Brazilian strains, which could tolerate NaCl up to 0.5% in the agar medium.
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