Biological Deacidification and High-Value Transformation of Acidic Citrus Pulp by Multi-Microbial Fermentation

Area of Science:

• Biotechnology
• Food Science
• Microbiology

Background:

• Citrus pulp's high acidity limits its use as an industrial byproduct.
• Developing sustainable methods to valorize citrus waste is crucial.

Purpose of the Study:

• To develop a microbial consortium for biological deacidification of citrus pulp.
• To evaluate the potential of the deacidified pulp as a biostimulant for plant growth.

Main Methods:

• Construction of a microbial consortium (BsHpMrF) including Bacillus subtilis, Hanseniaspora pseudoguilliermondii, and Monascus ruber.
• Analysis of total acidity reduction, metabolomics, and bioactive compound identification.
• Application assays using the fermented product on soybean sprouts.

Main Results:

• The microbial consortium achieved an 88.23% reduction in total acidity.
• Metabolomics revealed organic acid mineralization via TCA cycle and glyoxylate shunt, and lipid remodeling for acid tolerance.
• Fermentation enriched the pulp with bioactive lipids and indole-3-acetic acid (IAA), acting as a potent biostimulant for soybean sprouts, promoting growth and antioxidant accumulation.

Conclusions:

• A functional microbial consortium effectively deacidifies citrus pulp, creating a bio-stabilized substrate.
• The process valorizes citrus waste into a functional biostimulant, promoting sustainable agriculture and a circular economy.