Chemical analysis and biorefinery of red algae Kappaphycus alvarezii for efficient production of glucose from residue of carrageenan extraction process

Author(s)

Masarin, Fernando ^[1] ; Paz Cedeno, Fernando Roberto ^[1] ; Solorzano Chavez, Eddyn Gabriel ^[1] ; de Oliveira, Levi Ezequiel ^[2] ; Gelli, Valeria Cress ^[3] ; Monti, Rubens ^[4]

Affiliation

^[1] Univ Estadual Paulista, Dept Bioproc & Biotecnol, Fac Ciencias Farmaceut, UNESP, BR-14800903 Araraquara, SP - Brazil

^[2] Univ Sao Paulo, Dept Engn Quim, Escola Engn Lorena, CP 116, BR-12602810 Lorena, SP - Brazil

^[3] Secretaria Agr & Abastecimento Estado Sao Paulo, Inst Pesca Nucleo Pesquisa & Desenvolvimento Lito, Agencia Paulista Pesquisa Agr, Sao Paulo - Brazil

^[4] Univ Estadual Paulista, Dept Alimentos & Nutr, Fac Ciencias Farmaceut, UNESP, BR-14800903 Araraquara, SP - Brazil

• Document type: Journal article
• Source: BIOTECHNOLOGY FOR BIOFUELS; v. 9, JUN 10 2016.
• Web of Science Citations: 17

Abstract

Background: Biorefineries serve to efficiently utilize biomass and their by-products. Algal biorefineries are designed to generate bioproducts for commercial use. Due to the high carbohydrate content of algal biomass, biorefinery to generate biofuels, such as bioethanol, is of great interest. Carrageenan is a predominant polysaccharide hydrocolloid found in red macroalgae and is widely used in food, cosmetics, and pharmaceuticals. In this study, we report the biorefinery of carrageenan derived from processing of experimental strains of the red macroalgae Kappaphycus alvarezii. Specifically, the chemical composition and enzymatic hydrolysis of the residue produced from carrageenan extraction were evaluated to determine the conditions for efficient generation of carbohydrate bioproducts. Results: The productivity and growth rates of K. alvarezii strains were assessed along with the chemical composition (total carbohydrates, ash, sulfate groups, proteins, insoluble aromatics, galacturonic acid, and lipids) of each strain. Two strains, brown and red, were selected based on their high growth rates and productivity and were treated with 6 % KOH for extraction of carrageenan. The yields of biomass from treatment with 6 % KOH solution of the brown and red strains were 89.3 and 89.5 %, respectively. The yields of carrageenan and its residue were 63.5 and 23 %, respectively, for the brown strain and 60 and 27.8 %, respectively, for the red strain. The residues from the brown and red strains were assessed to detect any potential bioproducts. The galactan, ash, protein, insoluble aromatics, and sulfate groups of the residue were reduced to comparable extents for the two strains. However, KOH treatment did not reduce the content of glucan in the residue from either strain. Glucose was produced by enzymatic hydrolysis for 72 h using both strains. The glucan conversion was 100 % for both strains, and the concentrations of glucose from the brown and red strains were 13.7 and 11.5 g L-1, respectively. The present results highlight the efficiency of generating a key bioproduct from carrageenan residue. Conclusions: This study demonstrates the potential for glucose production using carrageenan residue. Thus, the biorefinery of K. alvarezii can be exploited not only to produce carrageenan, but also to generate glucose for future use in biofuel production. (AU)

• FAPESP's process: 14/05969-2 - Chemical characterization and saccharification of polysaccharides in different strains from macroalgae Kappaphycus alvarezii
• Grantee: Fernando Masarin
• Support Opportunities: Regular Research Grants