Fumaric acid production by fermentation

The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid from maleic anhydride and the fermentation process yields only 85% w/w from glucose, the latter raw material is three times cheaper. Besides, the fermentation fixes CO2. Production of fumaric acid by Rhizopus species and the involved metabolic pathways are reviewed. Submerged fermentation systems coupled with product recovery techniques seem to have achieved economically attractive yields and productivities. Future prospects for improvement of fumaric acid production include metabolic engineering approaches to achieve low pH fermentations

'Not all that burns is wood': a social perspective on fuel exploitation and use during the Indus urban period (2600-1900 BC)

Ancient civilisations depended heavily on natural fuel resources for a wide array of activities, and this had an impact on such resources that can be traced in the archaeological record. At its urban apex, the populations of the Indus Civilisation (2600–1900 BC) produced a wide range of objects and crafts, several of which involved highly specialised pyrotechnology. In the wake of increasing aridity and a period of weakened monsoon rainfall that affected South Asia from 2100 BC, these activities potentially put pressure on the natural resource base that may have had to be counterbalanced by differentiation in fuel use. The combined analysis of archaeobotanical and geoarchaeological remains from four Indus urban phase archaeological sites, has enable an assessment of the mechanisms through which people exploited wood, and diversified their fuel resources to adapt to the arid to semi-arid environments in which they lived. The combined use of local wood species with alternative fuels, such as dung and crop-processing leftovers, are evidence for resilient socio-ecological practices during the 700 years of Indus urbanism and perhaps beyond.The research was funded by AHRC Doctoral grant (2007/131224), St John’s College [no grant number], Cambridge European Trust (300469695) and The University of Cambridge (Isbel-Fletcher Garden Fund [no grant number], Smuts Memorial Fund [S2007/E2007], and Anthony Wilkin Fund [no grant number])