Friday, June 13, 2008


Dedini S.A. Ind. de Base;


Anhydrous fuel ethanol starting from molasses can be produced through several combined routes by application of different technologies for fermentation, distillation and dehydration processes. Indeed, they constitute chains of processes that must be driven by a specific objective, such as minimizing power consumption, steam consumption, losses, improving product quality or plant robustness, among others. The technology applied, however, has an initial investment, which can result in a less competitive plant, if that chain was not constructed under a strict sense of consistency and focused on real results. The present work shows a cross link among the main technologies pointing out their main features, and consistency in chains of production, in order to reach some specific purpose as described above, involving 1 - fermentation: continuous, batch, with or without yeast or vinasse recirculation, using centrifuges or floculant yeast; 2 - distillation: vacuum, pressurized, in cascade, with side streams or not; 3 – Dehydration: mol sieves, extractive and azeotropic distillation and vapour permeation through membranes, with liquid or vapour phase feed. The study concluded that each technology has its optimum in performance for each application in a different chain of technology for the whole process. For instance, some applications of vacuum distillation, fermentation under high yeast stress or with very special yeasts, dehydration under unsuitable route, etc. may be useless for some purposes and may have higher costs in maintenance, product quality control, high process sensitivity etc., despite their higher initial investments. On the other hand, neglecting these technologies may lead the project to a poor approach and consequently to a plant or process unbalanced and inefficient. It is very important to note that both pictures represent a business of lower competitiveness, especially in the case where the chosen technology chain is not robust enough.

KEYWORDS: Ethanol Process, Fermentation, Distillation, Dehydration

ISSCT XXVIth CONGRESS Durban, South Africa 29th July - 2nd August 2007)

Monday, June 2, 2008


R. Mungaroo, K.T.K.F. Kong Win Chang, A.S. Saumtally, J-F.Y. Moutia, M.H.R. Khoodoo and G.Triton
Mauritius Sugar Industry Research Institute, Reduit, Mauritius


For the sustainability of the Mauritian sugar industry, more co-products need to be produced from sugarcane biomass. One of the co-products that is currently being investigated at the Mauritius Sugar Industry Research Institute (MSIRI) is poly(3-hydroxyalkanoates), more commonly known as PHAs or bioplastics.
Cane juice, molasses and bagasse were chosen as raw materials for this study. The sucrose present in cane juice and molasses was quantitatively converted into simple sugars by dilute acids. Pretreated bagasse was converted into simple sugars by either acid or enzymatic hydrolysis, with emphasis being laid on the latter. Enzymes have been produced in situ by Trichoderma viride and T. harzianum. Media were prepared with the simple sugars obtained from the hydrolysis of sucrose and bagasse, and were inoculated with Ralstonia eutropha H16 G+ and Azospirillum spp. The bacterial cells were harvested, washed, freeze-dried and subjected to solvent extraction. Upon the removal of the solvents, biopolymers were obtained.
Once the yields for the production of simple sugars and PHAs have been optimized, the production of these biopolymers will be scaled up. Upon the successful completion of this study, the expertise will be shared with the sugar/plastic industry with the aim of making the commercial production of PHAs a reality in Mauritius. This could not only make the local sugar-cane industry more sustainable, but it could also enable the country to be less dependent on traditional petroleum-derived non-biodegradable (polluting) plastics.

KEYWORDS: Sugar-cane biomass, Hydrolysis, Ralstonia eutropha H16 G+, Azospirillum spp., Poly(3-hydroxyalkanoates)
(ISSCT XXVIth CONGRESS Durban, South Africa 29th July - 2nd August 2007)