In addition, the metal tolerance of the species in the literature and the microbial consortium used in this paper are shown in Table 2.
Heavy metal tolerance of P. putida LS46 has not been investigated, but this strain encodes genes for heavy metal resistance present in genomic region 1 of P. putida W619.
The role of these genes in heavy metal tolerance of S. maltophilia has not been clearly evidenced yet.
Therefore, HMTs are expected to increase heavy metal tolerance of organisms that lack the capacity to produce PC.
Consistent with this, Preveral and colleagues showed that SpHMT-1 increases heavy metal tolerance of E. coli and S. cerevisiae, whose genomes lack PC synthase homologs [10].
This confirms the previously observed metal tolerance of S. smithiana.
On the other hand, in most of the relevant literature [ 4, 45], heavy metal tolerances of non-metallicolous species (populations) have been compared to those of metallicolous ones.
In addition, it was confirmed that neither phosphate buffer nor carbon source concentration present in GYM Streptomyces medium caused an overestimated metals tolerance of strains, justified by the different tolerance range found in both strains and its mostly correlation with the results described by Gtari et al. [ 11].
Many Microbacterium spp. play a significant role in human health, industry, agriculture, environment, bioengineering, and biotechnology and have applicability in the production of exopolysaccharide, degradation of oil, degradation of xylan, metal tolerance, production of biosurfactants, degradation of dimethylsulphide, degradation of lactone, and as a growth promoter in plants [ 28].
In the present study, different concentrations of zinc (Zn2+) (0.5, 5, 10, 15, 20 mg/l) and lead (Pb2+) (1, 2, 4, 6, 8 mg/l) were used to evaluate metal tolerance level of Lemna minor.
Foods contaminated with heavy metal tolerance profile of different native or gene-modified plant species had been applied [ 33- 39].
