Skip to main content

DIRECT MICROBIAL BIOCONVERSION OF PRETREATED LIGNOCELLULOSIC MATERIALS TO FUEL ETHANOL.

Objective



THE POTENTIAL FOR DIRECT BIOCONVERSION OF LIGNOCELLULOSIC MATERIALS TO ETHANOL AND OTHER VALUABLE BY-PRODUCTS WILL BE INVESTIGATED BY EXPERIMENTAL AND THEORETICAL STUDY, ACCORDING TO THE FOLLOWING SCHEME:

- PHASE I.
EXTENSIVE AND IN-DEPTH CRITICAL REVIEW OF THE EXISTING AND/OR PROPOSED PROCESSES FOR DIRECT BIOCONVERSION IN RELATION TO PRETREATMENT. THIS PHASE IS EXPECTED TO BE OVER IN LESS THAN SIX MONTHS AND ITS RESULTS AND RECOMMENDATIONS WILL FORM PART OF THE FIRST PROGRESS REPORT.

- PHASE II.
EXPERIMENTAL STUDY OF MOST PROMISING PHYSICO-CHEMICAL PRETREATMENTS OF LIGNOCELLULOSE, IN ORDER TO APPROPRIATELY " TAILOR " A PRETREATMENT SEQUENCE TO THE PARTICULAR NEEDS OF THE MICROBIAL SYSTEMS UNDER INVESTIGATION IN THE PARALLEL PHASES 3 AND 4, AS FAR AS LIGNIN CONTENT, CRYSTALLINITY INDEX, SURFACE AREA, DP OF POSACCHARIDES, ROLE OF HEMICELLULOSE ETC... THE IDEA IS TO SELECT THE OPTIMAL SEQUENCE THAT WOULD ENHANCE ALL ENZYMIC AND MICROBIAL ACTIONS INVOLVED IN THE PROCESS.

- PHASE III:
EXPERIMENTAL STUDY OF THE PRODUCTION AND SELECTION OF FUNGAL MUTANT STRAINS, WHICH CAN BOTH EXTENSIVELY HYDROLYSE CELLULOSE TO GLUCOSE AND EFFICIENTLY FERMENT THE SUGARS PRODUCED TO ETHANOL. IN PARTICULAR, THIS PHASE INVOLVES THE SELECTION OF THOSE MUTANTS THAT HAVE ALREADY BEEN OBSERVED AT A PRELIMINARY EXAMINATION BY DR B MACRIS AT NRC " DEMOKRITOS " (FUSARIUM SP) AND WERE FOUND CAPABLE OF FERMENTING BOTH HEXOSES AND PENTOSES FROM VARIOUS SOURCES TO ETHANOL. STRAIN IMPROVEMENT TECHNIQUES TO BE USED INCLUDE INDUCTION OF MUTANTS WITH UV OR GAMMA IRRADIATION, SCREENING OF THE MUTANTS ON SOLID LIGNOCELLULOSIC SUBSTRATES, ISOLATION OF COLONIES SHOWING THE BEST GROWTH, AND EVALUATION OF THOSE MUTANTS WHICH WILL HAVE SHOWN THE BEST ETHANOL YIELDS AND RATES IN BOTH GLUCOSE AND XYLOSE FERMENTATIONS.

- PHASE IIII.
USE OF MIXED CULTURES OF PROPERLY SELECTED FUNGAL MUTANTS IN THE DUAL PURPOSE TO IMPROVE CELLULOSE SACCHARIFICATION AND ETHANOL FERMENTATION, AS FAR AS THE RATE AND THE YIELD ARE CONCERNED.
IN PARTICULAR, THIS PHASE INVOLVES THE STUDY OF THE INFLUENCE OF THE VARIOUS PRETREATMENTS ALREADY SELECTED IN PHASE 2 ON BOTH HYDROLYSIS AND FERMENTATION; THE ENHANCEMENT OF ETHANOL PRODUCTION THROUGH THE USE OF MIXED CULTURES OF ALREADY SELECTED IN PHASE 3 FUNGAL MUTANTS, ALONE OR IN COMBINATION TO ETHANOL-PRODUCING YEASTS; THE INVESTIGATION OF OPTIMAL CONDITIONS FOR FERMENTATION - N.B. THE WHOLE PROCESS INVOLVES BOTH AEROBIC (GROWTH OF FUNGI AND CELLULASE PRODUCTION, AS WELL AS THE FIRST STEPS OF XYLOSE METABOLISM) AND ANAEROBIC (GLUCOSE METABOLISM) STEPS.

- PHASE V.
SYNTHESIS OF THE RESULTS FROM THE PREVIOUS PHASES 1-4 TO FORM A MEANINGFUL PROCESS, FOLLOWED BY A COMPLETE EVALUATION OF THE TECHNICO-ECONOMIC VIABILITY AND ENERGY EFFICIENCY OF THE NOVEL PROCESS.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

NATIONAL TECHNICAL UNIVERSITY OF ATHENS
Address
9,Heroon Polytechniou 9
15780 Athens
Greece