A biorefinery is an arrangement of processes in which biofuels, bioproducts and bioenergy are produced from a biomass feedstock. In the processes are involved three main stages: pretreatment, reaction and separation. Each one of them could be performed with different technologies or process configurations.
Plantain Empty Fruit Bunches (PEFB) is a lignocellulosic non woody-stalk that gives support to plantain bunch. It is classified as an agricultural primary residue; its classification has been explained due to the nature of the source that is directly related with the seeding, development and harvesting of crops. Being a second generation feedstock it does neither need special treatment nor threat with food security. This fact converts this agriculture residue into a potential feedstock for biotechnological processes.
Lignocellulosic feedstocks are mainly composed by cellulose, hemicellulose and lignin. Degree of polymerization and crystallinity reduction are the principal objectives for lignocellulosic material pretreatment. The enhancement of the cellulose available surface area and lignin matrix destruction could be allowed by hydrothermal, acid, alkaline and organosolv pretreatment. These conventional operations could lead to some inhibitors compounds that affect the fermentation yields and the microorganism behaviors. Some non- conventional operations have been studied to enhance the pre-treatment stage of the lignocellulosic materials, such as ultrasonic and supercritical hydrolysis. Ultrasonic technology is based on acoustic radiation phenomena in which mechanic energy form is transformed to chemical energy generating chemicals, physicals and biochemical energies [1]. Ultrasonic waves are the expression of this kind of energy they create pressure drops at frequencies beyond audible range between 20-1000 kHz. They phenomenon could generate bubbles that produce shock waves which create a flow patterns generating a hydrodynamic shear stress capable of inducing changes in the lignocellulosic material structure. Hydrolysis at supercritical conditions could enhance the release of reducing sugars due to interactions experimented by enzymes in non-aqueous solvents that are similar to those in its native environment. Based on this, enzymes at supercritical conditions show higher activity than in pure water. Additionally the use of supercritical fluids offers a better control in selectiveness, reaction rates and product recovery [2][3]..
The aim of this work was to analyze the influence of non-conventional operations on productions yields of a biorefinery through the evaluation of supercritical enzymatic hydrolysis, ultrasonic pretreatment and conventional hydrolysis using PEFB as raw material.
PEFB was experimentally characterized by measuring moisture content (AOAC 928.09 method), klason lignin content (TAPPI 222 om-83 method), acid-soluble lignin content (TAPPI 250UM-85 method) holocellulose content (ASTM Standard D1104 method), cellulose content (TAPPI 203 os-

74 method), and ash content (TAPPI Standard T211 om-93 method). Then the three different hydrolysis schemes were experimentally evaluated in the Biotechnology and Agrobusiness Institute at the Universidad Nacional de Colombia at Manizales.

The PEFB biorefiney was evaluated in two scenarios using the commercial software Aspen Plus V8.0 (ASPEN TECHNOLOGY INC). The first scenario was evaluated for ethanol, PHB (Polyhydroxy butirate), xylitol and energy production using supercritical enzymatic hydrolysis. The second was evaluated for ethanol, PHB (Polyhydroxy butirate), xylitol and energy production using ultrasonic pretreatment and the third scenario was evaluated for ethanol, PHB (Polyhydroxy butirate), xylitol and energy production using conventional hydrolysis reactions. The economic evaluation was realized using the software commercial Aspen Process Ecomomic Analyzer V8.0 (ASPEN TECHNOLOGY INC) taking into account the Colombian context with an annual interest rate of 16% and an income tax of
25%, with electricity and water costs according to the case study conditions. Furthermore the evaluation was realized for a period of 10 years using as depreciation method the straight-line. The environmental evaluation was made through the methodology proposed by the Environmental Protection Agency (EPA) denominated Waste Algorithm Reduction (WAR). This tool evaluates from the mass and energetic balance the Potential Environmental Impact (PEI) of process generated by kg of product.

The best performance was selected based on the economical and environmental results based on the behavior of non-conventional and conventional operations. As a result of this work, it could be concluded that non-conventional operations represents an attractive alternative for process development with rigorous fermentations conditions.

REFERENCES

[1] L. E. Robles Ozuna and L. A. Ochoa-Martínez, â??Ultrasonido y sus Aplicaciones en el procesamiento de Alimentos.,â? Rev. Iberoam. Tecnol. Postcosecha, vol. 13, pp.
109â??122, 2012.
[2] G. Muratov and C. Kim, â??Enzymatic hydrolysis of cotton fibers in supercritical
CO2,â? Biotechnol. Bioprocess Eng., vol. 7, no. 2, pp. 85â??88, Apr. 2002.

[3] C. Y. Park, Y. W. Ryu, C. Kim, A. Univezzity, and S. C. Dioxide, "Kinetics and Rate of Ezymatic Hydrolysis of Cellulose in Supercritical Carbon Dioxide," Korean J. Chem. Eng., vol. 18, no. 4, pp. 475-478, 1994.