In the quest for sustainable agriculture, a team of researchers led by K. M. P. I. Jayathilake, P. M. Manage, and F. S. Idroos has made a significant stride by isolating and characterizing phosphate-solubilizing bacteria (PSB) from compost and open dump sites. Their findings, published in ‘Nature Environment and Pollution Technology’ (translated as ‘Nature Environmental and Pollution Technology’), could revolutionize how we approach plant nutrition and soil health, with profound implications for the energy sector.
Phosphorus is a critical macronutrient for plant growth, yet its bioavailability in soils is often limited due to its insolubility. The researchers aimed to tackle this challenge by identifying and characterizing PSB strains that can enhance phosphorus availability. “The isolation and characterization of these bacteria are crucial for developing bio-inoculants that can promote sustainable agriculture,” explained Jayathilake.
The study involved analyzing soil parameters such as pH, electrical conductivity, total organic carbon, organic nitrogen, and available phosphorus. Using Pikovskaya’s Agar (PKV), the team isolated five Bacillus strains: Bacillus pumilus strain PRE14, Bacillus altitudinis 41KF2b, Bacillus cereus ATCC 14579, Bacillus siamensis strain KCTC 13613, and Bacillus subtilis strain NCIB 3610. These strains were identified through biochemical tests and 16S rRNA gene sequencing.
The solubilization efficiency of the isolates was assessed in PVK broth supplemented with 0.5% tricalcium phosphate (TCP). The results were promising, with Bacillus siamensis strain KCTC 13613 showing the highest phosphate solubilizing efficiency, achieving a maximum phosphorus concentration of 9.17±0.07 mg/kg after just six days of incubation.
The impact of these bacteria on plant growth was evaluated in pot experiments using mung bean (Vigna radiata) as the experimental plant. The results were striking. Potting media inoculated with B. siamensis strain KCTC 13613 exhibited the highest shoot length (mean increase of 16.77 ± 0.74 cm), root length (mean increase of 10.99 ± 0.41 cm), and wet weight (mean increase of 0.60 ± 0.08 g) compared to other isolated PSB strains. “These findings demonstrate the potential of Bacillus spp. as bio-inoculants to enhance phosphorus availability and promote plant growth,” said Manage.
The study also revealed that soil pH increased post-germination, with the lowest pH recorded at 7.40±0.09 for media inoculated with B. siamensis strain KCTC 13613, indicating organic acid production. This finding suggests that these bacteria not only solubilize phosphorus but also improve soil health.
The implications of this research are far-reaching. In the energy sector, sustainable agriculture practices can reduce the environmental footprint of bioenergy crops, making them more viable and eco-friendly. By enhancing phosphorus availability and plant growth, these bio-inoculants can increase crop yields and improve soil fertility, ultimately contributing to more sustainable and productive agricultural systems.
As we look to the future, the potential applications of these phosphate-solubilizing bacteria are vast. From improving crop yields in marginal soils to enhancing the sustainability of bioenergy production, this research opens new avenues for innovation in agriculture and beyond. The work of Jayathilake, Manage, and Idroos is a testament to the power of scientific inquiry and its potential to drive positive change in the world.