Skip to main content

Valorization of sugar beet pulp by solid state fermentation

Objective

The solid state fermentation process (SSF) is well known in traditional food preparations and for such applications as fodder silage and composting.

The basic purpose of the proposed project is to apply SSF, using sugar beet pulp as the main substrate, for the manufacture of medium or high added value products. Previous experiences have shown the feasibility of such an operation for the production of protein enriched pulp and industrial enzymes. The production of pectinases by A. niger, currently being industrialized, has shown significant economical advantages compared to existing processes (deep tank, surface or Koji fermentation).

The object of the proposed research is to explore the most promising developments in solid state fermentation using sugar beet pulp as a substrate. The main research programme will involve microbiology, fermentation process optimization, engineering and nutritional tests. It will be conducted mainly at pilot plant scale. The anticipated outlets are in the improvement of feed composition for monogastric and polygastric animals, saccharification, protein enrichment and probiotics, and in the production of secondary metabolites such as enzymes, vitamins and amino acids.
The basic purpose of the project was to apply solid state fermentation (SSF) for the manufacture of medium or high added value products. Previous experiences have shown the feasibility of such an operation for the production of protein enriched pulp and industrial enzymes. The industrial production of pectinases by Aspergillus niger has shown significant economical advantages compared to existing processes (ie deep tank, surface or Koji fermentation). Sugar beet pulp is already an excess feedstuff in some European countries. The continuing trend towards decreased dairy production in the European Community (EC) will cause further pressure on sugar beet pulp sales into this market. A new outlet is very important for the future. The object of the research is to explore the most promising developments in SSF using sugar beet pulp as a substrate.
Analytical methods for the measurement of enzyme activity were developed and various strains of fungi were screened for the production of the desired enzymes, with mutagenesis and genetic engineering being conducted to increase productivity. Optimum fermentation conditions have also been studied for the different microorganisms.

Solid state fermentation (SSF), using sugar beet pulp as the main substrate, is being developed for the manufacture of medium of high added value products. The production of industrial enzymes to be used for animal feed improvement and other applications is under study. Analytical methods for the measure of enzyme activity were developed. Collection strains of different species of fungi were screened for the production of the desired enzymes. For the selected strains, mutagenesis was conducted to increase the productivity. At the same time, optimum fermentation conditions have been studied for the different microorganisms: compositions of the substrate; water content; temperature; and duration. After development in flask and laboratory fermenters, experiments are being conducted in 50 l pilot fermenters. Genetical engineering was used to obtain one highly productive strain of fungus.

The production of protein enriched beet pulp and probiotic enriched beet pulp is under study. For both studies, suitable strains were selected, and the nutritional quality of fermented beet pulp was evaluated. Fermentation media and fermentation conditions were developed from flask to laboratory fermenters.

Animal feed evaluation and an animal feed experiment was undertaken. In the experiment on broiler chickens positive results due to the addition of enzymes were observed.
The main advantages are the following:
high volumetric productivity due to the high concentration of substrate per unit volume of fermenter;
low capital investment;
facility of product recovery and drying;
reduction of chemical and biological oxygen demand;
possibility to recover the secondary metabolites at a high concentration;
low energy consumption.

Sugar beet pulp is an excellent substrate for SSF:
it has a satisfactory composition and is a suitable carbon source for microbial utilization;
it has a rigid and open structure allowing a specific reactor design;
pulp particles are loose and not sticky;
it has a high water holding capacity allowing solubilization of nutrients;
it is available in large quantities at low cost.

Sugar beet pulp is already an excess feedstuff in some European countries. The continuing trend for decreased dairy production in the EC will cause further pressure on sugar beet pulp sales into this market. A new outlet is very important for the future.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Générale Sucrière
Address
25 Avenue Franklin D Roosevelt
75008 Paris
France

Participants (6)

British Sugar plc
United Kingdom
Address
Colney Lane
NR4 7UB Norwich
Compañía de Industrias Agrícolas SA
Spain
Address
103,C/balmes
08008 Barcelona
Enzymatix Ltd
United Kingdom
Address
Cambridge Science Park Milton Road
CB4 4WE Cambridge
LYVEN S.A.
France
Address
Route De Paris
14630 Cagny
Solvay S.A.
Belgium
Address
310,Rue De Ransbeek
1120 Bruxelles
Südzucker AG
Germany
Address
Wormsetr Straße 11
67283 Obrigheim