Document Type: Review Paper
Programa de Celulosa y Papel - Instituto de Materiales de Misiones (CONICET-UNaM), Facultad de Ciencias Exactas Químicas y Naturales, Félix de Azara 1552 (3300), Misiones, Argentina.
There is a global interest in replacing fossil fuels with renewable sources of energy. The present review evaluates the significance of South-American wood industrial wastes for bioethanol production. Four countries have been chosen for this review, i.e., Argentina, Brazil, Chile, and Uruguay, based on their current or potential forestry industry. It should be noted that although Brazil has a global bioethanol market share of 25%, its production is mainly first-generation bioethanol from sugarcane. The situation in the other countries is even worse, in spite of the fact that they have regulatory frameworks in place already allowing the substitution of a percentage of gasoline by ethanol. Pines and eucalyptus are the usually forested plants in these countries, and their industrial wastes, as chips and sawdust, could serve as promising raw materials to produce second-generation bioethanol in the context of a forest biorefinery. The process to convert woody biomass involves three stages: pretreatment, enzymatic saccharification, and fermentation. The operational conditions of the pretreatment method used are generally defined according to the physical and chemical characteristics of the raw materials and subsequently determine the characteristics of the treated substrates. This article also reviews and discusses the available pretreatment technologies for eucalyptus and pines applicable to South-American industrial wood wastes, their enzymatic hydrolysis yields, and the feasibility of implementing such processes in the mentioned countries in the frame of a biorefinery.
- Second generation bioethanol is a viable option to valorize the residues of the South America forest industry.
- Eucalyptus and pines are the most important woody raw materials in the region.
- Autohydrolysis and alkaline treatments are effective options to pretreat Eucalyptus.
- Novel and complex treatments or treatment combinations are recommended for pine-based ethanol production.
- Raw material price plays a key role in the cost distribution of cellulosic bioethanol.