Novel strategy for the production of a generic fermentation feedstock based on particulate bioprocessing
Sustainable process-product development & green chemistry
Sustainable & Clean Technologies - IIa: Energy Production (T1-5a)
Keywords: particulate bioprocessing, solid state fermentation, generic feedstock, cereals, biofuels, bioplastics
There is an increasing social and political demand to replace traditional chemical processes with more benign and sustainable, biotechnology based, processes. At the same time there is a growing desire to establish renewable feedstocks which can decrease our dependency on dwindling oil reserves, and reduce greenhouse gas emissions. However biotechnological processes generally require the use of relatively expensive raw materials and large amounts of water and are therefore often uncompetitive. Research in the Satake Centre for Grain Process Engineering is aimed at overcoming these limitations through the development of generic fermentation feedstocks using cereals as raw material.
As part of this goal we are developing a novel process strategy (particulate bioprocessing) based on solid state fermentation (SSF) for the production of a generic microbial feedstock that can be used for the production of value-added chemicals or biofuels.
The process proposed involves two main fermentation steps. In the first one a packed bed of partially pearled whole wheat grains is used for fermentation by the fungus Aspergillus awamori. Intermittent addition of water during the cultivation helps to maintain moisture and temperature levels, and is also used to extract soluble components. The extracts obtained have high glucose and free amino nitrogen (FAN) concentrations and have been used for subsequent fermentations by Wautersia eutropha to produce the biodegradable plastic PHB (Polyhydroxybutyrate) and by Sacharomyces cerevisiae for ethanol production
Preliminary studies on the effects of pearling, initial moisture content and addition of water have been carried out, followed by more detailed studies on mixing, scale up, and the duration between extractions. Extracts with high glucose (190 g/L) and FAN (1.7g/L) concentrations were successfully produced with starch to glucose conversion yields of up to 70%.
Results of subsequent fermentations using the extracts have already shown that they can be used successfully for the production of both PHB and ethanol and therefore contain the full range of nutrients required by a variety of microorganisms. The processing strategy based on particulate bioprocessing therefore has the potential to produce through, simple in-situ extraction, a generic feedstock that could be used for the production of a wide range of petrochemical replacements.
Presented Wednesday 19, 15:15 to 15:30, in session Sustainable & Clean Technologies - IIa: Energy Production (T1-5a).
