Aerobes and phototrophs as microbial organic fertilizers: Exploring mineralization, fertilization and plant protection features

Abstract

Organic fertilizers and especially microbial biomass, also known as microbial fertilizer, can enable a paradigm shift to the conventional fertilizer-to-food chain, particularly when produced on secondary resources. Microbial fertilizers are already common practice (e.g. Bloom® and Synagro); yet microbial fertilizer blends to align the nutrient release profile to the plant’s needs are, thus far, unexplored. Moreover, most research only focuses on direct fertilization effects without considering added value properties, such as disease prevention. This study has explored three promising types of microbial fertilizers, namely dried biomass from a consortium of aerobic heterotrophic bacteria, a microalga (Arthrospira platensis) and a purple non-sulfur bacterium (Rhodobacter sphaeroides). Mineralization and nitrification experiments showed that the nitrogen mineralization profile can be tuned to the plant’s needs by blending microbial fertilizers, without having toxic ammonium peaks. In a pot trial with perennial ryegrass (Lolium perenne L.), the performance of microbial fertilizers was similar to the reference organic fertilizer, with cumulative dry matter yields of 5.6–6.7 g per pot. This was confirmed in a pot trial with tomato (Solanum lycopersicum L.), showing an average total plant length of 90–99 cm after a growing period of 62 days for the reference organic fertilizer and the microbial fertilizers. Moreover, tomato plants artificially infected with powdery mildew (Oidium neolycopersici), a devastating disease for the horticultural industry, showed reduced disease symptoms when A. platensis was present in the growing medium. These findings strengthen the application potential of this novel class of organic fertilizers in the bioeconomy, with a promising match between nutrient mineralization and plant requirements as well as added value in crop protection.

Foliar Spray or Soil Drench: Microalgae Application Impacts on Soil Microbiology, Morpho-Physiological and Biochemical Responses, Oil and Fatty Acid Profiles of Chia Plants under Alkaline Stress

“…The favorable seed and oil yields obtained in the current study may be due to the positive effect of microalgae as a high-value organic and growth regulator [ 58 ]. Additionally, this may be because microalgae have a positive effect on relative water content and nutrient status [ 59 ], increasing the ability for leaf metabolism, cell elongation, and expansion [ 60 ], as well as providing effective regulation of primarily the zinc finger protein-160 [ 61 ].…”

Effects of Different Proportions of Organic Fertilizer Replacing Chemical Fertilizer on Soil Nutrients and Fertilizer Utilization in Gray Desert Soil

“…Fertilization can maintain high and stable wheat yield by influencing the components of the wheat [2,3]. Because of the excessive pursuit of high wheat yield, farmers increase the amount of fertilizer applied; this unreasonable over-application of fertilizer not only reduces the fertilizer utilization rate but also promotes soil acidification and salinization, which have adverse consequences [4][5][6].…”

Aggregation of purple bacteria in an upflow photobioreactor to facilitate solid/liquid separation: Impact of organic loading rate, hydraulic retention time and water composition

“…In resource recovery, PNSB are typically exploited in photohetero-or -mixotrophic mode where they use light as energy source and organics optionally in combination with inorganic carbon as carbon source(s). Different value-added products have been investigated for resource recovery by PNSB such as microbial protein, fertilizers and polyhydroxyalkanoates (Wambacq et al, 2022;Alloul et al, 2021;Capson-Tojo et al, 2020;Sakarika et al, 2020). Research to efficiently harvest PNSB-rich biomass is, however, limited.…”