Fermentation Strategies to Improve Soil Bio-Inoculant Production and Quality

Abstract

The application of plant beneficial microorganisms has been widely accepted as an efficient alternative to chemical fertilizers and pesticides. Isolation and selection of efficient microorganisms, their characterization and testing in soil-plant systems are well studied. However, the production stage and formulation of the final products are not in the focus of the research, which affects the achievement of stable and consistent results in the field. Recent analysis of the field of plant beneficial microorganisms suggests a more integrated view on soil inoculants with a special emphasis on the inoculant production process, including fermentation, formulation, processes, and additives. This mini-review describes the different groups of fermentation processes and their characteristics, bearing in mind different factors, both nutritional and operational, which affect the biomass/spores yield and microbial metabolite activity. The characteristics of the final products of fermentation process optimization strategies determine further steps of development of the microbial inoculants. Submerged liquid and solid-state fermentation processes, fed-batch operations, immobilized cell systems, and production of arbuscular mycorrhiza are presented and their advantages and disadvantages are discussed. Recommendations for further development of the fermentation strategies for biofertilizer production are also considered.

Evaluation of a new antimicrobial agent production (RSMM C3) by using metagenomics approaches from Egyptian marine biota

“…The finest part of the process was the stationary phase and the best phase for developing antimicrobial agents at various stages of growth [ 40 ]. For successful and effective fermentation of a specific bioactive molecule and high product yields, the performance of a supporting production medium was critical [ 41 , 42 ].…”

Degradation activity of fungal communities on avocado peel (Persea americana Mill.) in a solid-state process: mycobiota successions and trophic guild shifts

“…Another plausible explanation of the observed behavior relies on the solid-state degradation system employed here. Although the mixes were regularly homogenized, the distinct proportions of loan and clay from soil added to the mix in each treatment may form different microenvironments, biofilms, or chelating conditions altering the availability of micronutrients, oxygen, water, and light for the microbial community (Vassileva et al 2021).…”

Safety Level of Microorganism-Bearing Products Applied in Soil-Plant Systems

“…All operations starting from the inoculum preparation, fermentation process, and downstream stage, including the product formulation as well as packaging, are carried out in sterile conditions, and, therefore, these biotechnological products should be free of contaminants. The production of spores, biomass, or metabolites is normally carried out in closed liquid submerged (e.g., batch and fed-batch) or solid-state fermentation systems with well-controlled parameters and improved quality of the final product ( Vassileva et al, 2021 ). However, there is a risk of biological contamination in each one of the production process stages deriving from water, air, equipment, nutrient media, and laboratory/plant technical staff.…”