Sustainable conversion of coffee and other crop wastes to biofuels and bioproducts using coupled biochemical and thermochemical processes in a multi-stage biorefinery concept

Abstract

The environmental impact of agricultural waste from the processing of food and feed crops is an increasing concern worldwide. Concerted efforts are underway to develop sustainable practices for the disposal of residues from the processing of such crops as coffee, sugarcane, or corn. Coffee is crucial to the economies of many countries because its cultivation, processing, trading, and marketing provide employment for millions of people. In coffee-producing countries, improved technology for treatment of the significant amounts of coffee waste is critical to prevent ecological damage. This mini-review discusses a multi-stage biorefinery concept with the potential to convert waste produced at crop processing operations, such as coffee pulping stations, to valuable biofuels and bioproducts using biochemical and thermochemical conversion technologies. The initial bioconversion stage uses a mutant Kluyveromyces marxianus yeast strain to produce bioethanol from sugars. The resulting sugar-depleted solids (mostly protein) can be used in a second stage by the oleaginous yeast Yarrowia lipolytica to produce bio-based ammonia for fertilizer and are further degraded by Y. lipolytica proteases to peptides and free amino acids for animal feed. The lignocellulosic fraction can be ground and treated to release sugars for fermentation in a third stage by a recombinant cellulosic Saccharomyces cerevisiae, which can also be engineered to express valuable peptide products. The residual protein and lignin solids can be jet cooked and passed to a fourth-stage fermenter where Rhodotorula glutinis converts methane into isoprenoid intermediates. The residues can be combined and transferred into pyrocracking and hydroformylation reactions to convert ammonia, protein, isoprenes, lignins, and oils into renewable gas. Any remaining waste can be thermoconverted to biochar as a humus soil enhancer. The integration of multiple technologies for treatment of coffee waste has the potential to contribute to economic and environmental sustainability.

Microbial identification of potato taste defect from coffee beans

“…Potato flavor also may be detected during processes such as harvesting, transport from harvesting to washing stations, pulping, and fermentation (Hughes et al., ). In this study, earthy odor was found in all samples (No1 to No5) resulting from soil contamination associated with bacteria.…”

Tyrosinase mediated humic substances synthesis by Bacillus aryabhattai TFG5

“…Similarly, the coefficient E472/664 is associated with the level of condensation of the chain of aromatic carbons. Higher values at this coefficient indicate the presence of more aliphatic structures and less aromatic structures[39–42]. To further study the functional groups associated with humic substances, FT-IR analysis was performed, and the results are presented in Fig6.…”

Diagnóstico del agua utilizada en las procesadoras de café del Municipio Caripe – Estado Monagas, Venezuela.// Diagnosis of the water used in coffee processors of the Caripe Municipality - Monagas State, Venezuela

“…El agua es esencial para todas las formas de vida y en relación con el planeta, América Latina dispone de abundantes recursos naturales incluyendo grandes reservorios hídricos que sustentan en gran medida las amplias expectativas para el desarrollo bioeconómico de la región destacada por su gran producción de productos agrícolas para el mundo, donde el café representa el rubro más comercializado, luego del petróleo, con Brasil al frente como el mayor productor/ exportador a nivel mundial (Malavé y Maza, 2015); donde el agua conforma el recurso fundamental en la agroindustria cafetalera, la cual es crucial para la economía de muchos países Latinoamericanos al proporcionar empleo a millones de personas que participan en su cultivo, procesamiento, comercialización y mercadeo (Hughes et al, 2014).…”