Lysinibacillus sphaericus plant growth promoter bacteria and lead phytoremediation enhancer with Canavalia ensiformis

Abstract

Lysinibacillus sphaericus is known for its great larvicidal activity against mosquito larvae and toxic metal resistance, but knowledge about its possible activity in soil is scarce and poor. Nevertheless, in the genome of some strains have been reported genes of nitrogen cycle. Seven L. sphaericus strains were tested as nitrogen fixing bacteria, nitrifying bacteria, and indoleacetic acid producer. Subsequently a consortium was formulated using the best strains (CBAM5, III(3)7, OT4b.31, and OT4b.49) to evaluate its effect in Canavalia ensiformis growth and lead phytoremediation. All L. sphaericus strains were able to fix nitrogen (0.61–1.47 mg/L of ammonium), nitrify (0.26–0.7 mg/L of nitrate), and produce IAA (3.3–5.5 µg/mL in L‐tryptophan media and 0.3–1.1 µg/mL in trypticase broth). They also promoted shoot length, root length, foliar area, and leaf number in C. ensiformis, enhanced lead bioaccumulation in the root reaching a removal of 40% of lead in greenhouse experiment, and increased nitrate content in soil twofold in contrast to the control in field experiment. Therefore, L. sphaericus could be a key organism in the formulation of biofertilizers, as it shows potential in the phytoremediation processes, in crop plant nutrition, and growth in low nutrient polluted soils, then is a plant growth promoter bacteria (PGPB). © 2017 American Institute of Chemical Engineers Environ Prog, 37: 276–282, 2018

Lysinibacillus sphaericusas a Nutrient Enhancer during Fire-Impacted Soil Replantation

“…However, in contrast to these treatments, C and G controls showed a decreasing tendency. Nitri cation or denitri cation processes might in uence diminishing soil ammonium concentration [34], yet results exhibited that PGPB can help stabilize soil ammonium levels or even increase them when compared to soil with no bacteria, as shown in our results and in a previous study [11].…”

“…Bacteria whose activity affects soil chemical properties can be plant-growth promoting bacteria (PGPB). Part of the bacteria classified in this group are reported to play an important role in nitrogen and phosphorus cycling, since they have the ability to fix nitrogen, and nitrify, and solubilize phosphorus, increasing soil nutrients that plants use for their growth [11]. Studies reported the use of PGPB in soil restoration, showing an enhancement of soil nutrients when adding an inoculum of PGPB consortium in degraded soils during replantation with native trees [12] and the direct effect of these bacteria inoculum on plant growth [13].…”

“…Lysinibacillus sphaericus is a spore-forming, aerobic, and mesophilic Gram-positive bacterium. Previous studies reported the isolation of this bacterium from soil and water and its activity as a PGPB [11]. ere are also reports of L. sphaericus being used to promote the production of phytohormones, such as indole acetic acid (IAA) [11], involving in the radicular plant growth and plant nutrient uptake [14].…”

“…Previous studies reported the isolation of this bacterium from soil and water and its activity as a PGPB [11]. ere are also reports of L. sphaericus being used to promote the production of phytohormones, such as indole acetic acid (IAA) [11], involving in the radicular plant growth and plant nutrient uptake [14]. Furthermore, the genomes of L. sphaericus strains OT4b.31, CBAM5, and III(3)7 contain annotated genes that are involved in nitrogen cycling [11,[15][16][17].…”

Rhizospheric Bacteria, Destructors of Toxic Aromatic Compounds

“…Lysinibacteria are considered to be very promising agents for bioremediation. Bacteria of this genus can not only decompose stable pollutants, but also belong to the group a plant growth-promoting bacterium [14]. Stenotrophomonas sp.…”