Bioprocess reducing the solubility of rhizospheric cadmiun

This project proposes an innovative and environmentally friendly bioprocess to reduce the bioaccumulation of cadmium (Cd).

Context of the story

Successful marketing of Latin-American fine aroma national cocoa is hampered by high Cd content in the beans. This project proposes an innovative, highly efficient, and climatically-intelligent bioprocess that will reduce the bioaccumulation of Cd and presents protocols for its implementation in cocoa family farms (FF). Activities will be carried out via technical cooperation with scientists and farmers as well as private and governmental sectors. There will be 3,150 direct and 3,000 indirect beneficiaries involved in the cocoa value chain.

The aim of the project is to reduce the cocoa bean Cd concentration to values below 0.8 mg kg-1 dry weight in the cocoa plantations where this biotechnology will be installed.

The implemented initiative

The bioprocess will involve: (a) the isolation of a consortium of soil fungi native to cocoa plantations, that have the ability to decrease aerial and root Cd bioaccumulation (CB r,a) coefficients; (b) the assessment of the effectiveness of the bioprocess in bioreactors, and the elevation of cocoa family farms (FF) to Technology Readiness Levels (TRL) 6 and 7. Activities will be carried out via technical cooperation with scientists and farmers as well as private and governmental sectors.

To generate a bioprocess based on a fungal consortium that will reduce the Cd content in cocoa beans.

The technological solution

The goal of the project is to reduce Cd bioaccumulation in cocoa beans to values lower than 0.8 mg kg-1 dry weight via the management of soil microbiota. This biotechnology will be implemented in Ecuador and Venezuela, where assistance is currently being given to more than 30 cocoa farm owners, and 15 entrepreneurs are being trained, all being leading figures in their localities. This will enable improvements in living conditions and increases in income for beneficiaries. Emphasis will be on the advancement of the women involved (whether rural population, technicians, professionals or entrepreneurs). Media broadcasting are via networks, 13 published scientific papers and 3 theses.

“It’s the start of a new era, when people are finally ready to embrace the microbial world”

Ed Yong, science journalist

Participating countries

Type of project

Results

Present results show:
1. The high P-solubilizing efficiency of microbial populations native to soils under lemon plantations in Ecuador permits the growth of CN seedlings and eliminates the need for incorporating Cd-contaminated P fertilizers.
2. Saprobe fungi strains tolerant to high Cd concentrations exist in FV soils.
3. Phanerochaete chrysosporium, identified among the fungi collection at the Zaidin Experimental Station, is a saprobe species tolerant to high Cd concentrations.
4. TRL 4 bioreactors allow evaluation of the impact of varying Cd concentrations in cocoa seedlings.
5. The physico-chemical data obtained in the TRL 4 bioreactors can be upgraded to TRL 6 in plant purification modules while respecting the physical, chemical, and biological calibrations obtained at TRL 4.
6. Symbiotic effectiveness of the mycorrhizal strain was assessed in Baccharis salicifolia, with very high bioextractive potential of Cd.