Phosphorus Recycling from an Unexplored Source by Polyphosphate Accumulating Microalgae and Cyanobacteria—A Step to Phosphorus Security in Agriculture

Abstract

Phosphorus (P), an essential element required for crop growth has no substitute. The global food security depends on phosphorus availability in soil for crop production. World phosphorus reserves are fast depleting and with an annual increase of 2.3% in phosphorus demand, the current reserves will be exhausted in coming 50–100 years. India and other Western countries are forced to import phosphorus fertilizers at high costs to meet their agricultural demands due to uneven distribution of phosphate rocks on earth. The present study from India, aims to draw attention to an unnoticed source of phosphorus being wasted as parboiled rice mill effluent and subsequent bio-recovery of the valuable element from this unconventional source. The research was conducted in West Bengal, India, a state with the highest number of parboiled rice mills where its effluent carries on an average ~40 mg/L of soluble phosphorus. Technology to recover and recycle this wastewater P in India in a simple, inexpensive mode is yet to be optimized. Our strategy to use microalgae, Chlorella sp. and cyanobacteria, Cyanobacterium sp., Lyngbya sp., and Anabaena sp. to sequester the excess phosphorus from the effluent as polyphosphate inclusions and its subsequent recycling as slow and moderate release phosphorus biofertilizers to aid plant growth, preventing phosphorus loss and pollution, is a contemporary venture to meet the need of the hour. These polyphosphate accumulating microorganisms play a dual role of remediation and recovery of phosphorus, preliminarily validated in laboratory scale.

Evidence of oxygenic phototrophy in ancient phosphatic stromatolites from the Paleoproterozoic Vindhyan and Aravalli Supergroups, India

“…As opposed to the specific environments commonly inhabited by sulfur‐oxidizing bacteria, the Paleoproterozoic phosphatic stromatolites described herein seem to have been formed along a well‐lit, relatively shallow‐water carbonate platform, as indicated by the mineralogy, tufted cyanobacteria‐like filaments, and conspicuous multicellular red algae (e.g., Bengtson et al., ). Laboratory studies (e.g., Diaz et al., ; Mukherjee, Chowdhury, & Ray, ) show that modern oxygenic phototrophic microbial communities, for example cyanobacteria of Lyngbya type and diatoms, accumulate phosphate by internal polyP storage within their trichomes or frustules, indicating that cyanobacterial communities can be locally important in concentrating phosphate in shallow‐water sedimentary environments. Cyanobacteria also contribute to diurnally fluctuating pO 2 regimes within microbial mats, a feature that might be important for apatite precipitation, as it would help to establish steep local redox gradients, affecting the release of bioavailable phosphate within the mats.…”

Hyperconcentrated Sweet Whey, a New Culture Medium That Enhances Propionibacterium freudenreichii Stress Tolerance

“…In addition, polyphosphate granules were visualized by DAPI (4=,6=-diamidino-2-phenylindole) staining as previously described (30) and later modified (31) for cyanobacteria. Briefly, bacteria were washed in McIlvaine's buffer (31), fixed in 4% formaldehyde, permeabilized in 0.3% Triton X-100, and stained in 20 g/ml DAPI in the same buffer. The stained cultures were observed on an Olympus BX51 epifluorescence microscope equipped with a U-MWU2 fluorescence filter cube (excitation filter, 330 to 385 nm; emission filter, 480 to 800 nm) and an Olympus plan 100ϫ/1.25 oil objective.…”

Simultaneous sequestration of nitrate and phosphate from wastewater using a tailor‐made bacterial consortium in biofilm bioreactor

“…The cost of chemical treatment to remove it from water is high. Researchers have proposed the use of microalgae and cyanobacteria for entrapping phosphate from wastewater or effluent as biofertilizer …”