Simultaneous saccharification and fermentation of microwave - alkali pre-treated oil palm empty fruit bunch fiber for lactic acid production
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Date
2012
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Teknologi Malaysia
Abstract
The novelty of this study is the production of lactic acid from pre-treated oil palm empty fruit bunch (OPEFB) fibre via microwave–alkali (Mw-A) and simultaneous saccharification and fermentation (SSF) process with Rhizopus oryzae. The present work involved a pre – treatment of OPEFB using two different methods; the conventional heating–alkali and Mw-A techniques. Physical and chemical changes on OPEFB fibre, saccharification and hydrolysis process of treated OPEFB were identified for the evaluation of the accessibility of the treated OPEFB. Suitable conditions for R. oryzae morphology and effective SSF process of the treated OPEFB for lactic acid production were also investigated. Results revealed that the Mw-A technique is more effective pre – treatment for OPEFB compared to the conventional heating–alkali. Application of Mw-A on native OPEFB break the ligninhemicellulose seal, disrupted the crystalline structure of the cellulose and thus, resulted in reduction of the lignin and hemicelluloses composition. Reduction of lignin and hemicellulose through Mw-A was significantly increased an accessibility of the cellulose to the enzymatic attack. In fermentation of Mw-A treated OPEFB using R. oryzae, R. oryzae in pellet form was better than R. oryzae in the form of clump and ellipsoidal due to a higher production of lactic acid. The lactic acid production in SSF process was optimised using Face Centred Central Composite Design (FCCCD). The main effects considered were enzyme concentration (100 – 600 mgL-1), pH (4 – 6) and temperature (37°C – 50°C), and the response variables measured were lactic acid, glucose and protein concentration. From statistical analysis, the optimum lactic acid production was achieved at pH of the medium of 6 and temperature of 37°C. The cellulase concentration required to support production of 900 gL-1 of lactic acid at optimum condition was 600 mgL-1 (98.4 FPU ml-1 cellulase and 770 IU ml-1 ß 1-4 glucosidase). The present study revealed that through Mw-A technique, the cellulose molecule inside OPEFB are wisely utilized by enzyme and R. oryzae in order to produce optimum lactic acid in SSF process
Description
Thesis (PhD. (Bioprocess Engineering))
Keywords
Lignocellulose—Biotechnology, Saccharin, Lactic acid—Biotechnology