The plant growth promoting strains isolated from tannery
sludge and charaeteri/ed is Pseudomonas strain. The plant
growth promoting Pseudomonas pittidu can utilize 1-aniinocyclopropanc-l-carboxylase
(ACC) as a sole nitrogen source
because it possess the unusual enzyme ACC dcaminase, which
hydroly/es ACC to ammonia and a-ketobutyrate. This enzyme
which is though to be intimately involved in the mechanism
that the bacterium uses to promote root elongation in developing
seedlings, under field study was purified and characterized.
ACC deaminase activity is found in the cytoplasm of the
bacterium, is induced by low levels (l00nM) of ACC, and has a
temperature optimum at approximately 30’c and a pll optimum
of 8.5. These properties are very similar to those reported for
ACC” deaminase from another soil bacterium Pseudomonas
strain. In heavily contaminated soil, sludge where the pollutant
exceeds the limit of plant tolerance, it may be possible to
treat plant with plant growth promoting bacteria, increasing
plant growth on polluted soils.