A PLATFORM FOR THE VALORIZATION OF AGRICULTURE RESIDUES: HULLS FROM CROPS: SOYBEAN HULL

PICÓ, GUILLERMO; CAMISCIA, PAOLA; NADIA WOITOVICH VALETTI; GIORDANO, ENRIQUE DAVID VICTOR

Braga ,

Congreso; 3er C O N G R E S S O F B I O T E C H N O L O G Y Braga Portugal; 2022

Sociedad de Biotecnologia de Portugal

The process of the industrialization of crops (soybean, wheat, rice, corn, etc.) begins with the breakage of the grain by amechanical step releasing their hull or endocarp, which represents 2-20 % of the grain’s total mass. This percentage mayseem small, but taking into account the amounts of crops produced and industrialized every year worldwide, it actuallyrepresents millions of tons. These hulls have variable sizes, are considered a waste; they are inflammable since they easilyoxidized in contact with air, so they must be continuously eliminated from the place where they are produced, making its processing moreexpensive.The hull’s lignin content is important when selecting the type of biomass which will be used in any process, since a highcontent of this compound increases its hardness and, consequently, makes it more difficult to grind the material. SoybeanHull (SBH) is an excellent biomass to be used as raw material since it has a low lignin content (1-3%) facilitating itshandling. It also contains 12% soluble proteins, 9-11% galactomannans, 10-12% pectin, 9-10% hemicellulose, 40-50%cellulose. By using a leaching process with an aqueous phase [1] we have recovered the fraction of soluble proteins,which contain among others: Peroxidase, which has proven to be a good substitute of the existing commercial enzymesince it has mayor temperature resistance and better kinetic properties, and also various Kunitz trypsin inhibitor isoformsand Trypsin inhibitor, both with potential anticancer properties. The remaining solid residual phase, which containcellulose and lignin, was treated under an alkaline medium of 5% (w/v) NaOH during 40 h at 50 °C obtaining purecellulose (50% of amorphous structure) free of lignin with a yield of 80-83%. This cellulose is highly reactive meaning that acidic or basicgroups can be grafted obtaining an ion exchanger [2]. These non-expensive exchangers were used toisolate the peroxidase and the antitrypsin factors obtained in the leachate, and were also used in the bioremediation ofwastewaters contaminated with dyes from the textile industries [3]. A more in-depth analysis of the above, allows us toconclude that SBH is an excellent residue to be used as a source of different molecules of interest since it is produced inlarge quantities around the world, with the advantage that it presents low lignin content which favors its processing andalso in the bioremediation of the environment.