Economic and agronomic impact assessment of wheat straw based alkyl polyglucoside produced using green chemical approaches

Results from a previous environmental impact assessment highlight the potential for the proposed process, that converts low-value agricultural residue (wheat straw) into a high-value biosurfactant, to result in significant (>75%) GHG savings, relative to the commercial candidate derived from palm kernel and wheat grain. This was achieved via the use of low-energy techniques like supercritical CO2 extraction, low-temperature microwave and in-situ fractionation of platform chemicals. Despite the environmental benefits, process commercialization relies on the economic feasibility of the production. Adopting a ‘cradle-to-gate’ life cycle costing approach, this paper has quantified the economic feasibility and resource efficiency characteristics of producing wheat-straw based APG, via the previously suggested green low-waste generating processes. Here, we undertook economic analysis of a wheat straw-derived APG production pathway, in comparison to palm-kernel and wheat-grain APG. Total processing costs were determined to range between $0.92-$1.87 per kg of wheat straw-APG demonstrating relatively better output service quality and energy efficiency, while conventional APG costs $1.95-$2.87 per kg, highlighting the significant potential of the residue-derived pathway to be scaled to commercial-level. In addition, a semi-quantitative assessment of the demand-based implications of adopting and scaling-up the green process, in the current context and practices of wheat cultivation was also undertaken. Potential agronomic impact that might be result from such scale-up scenarios, focusing on the effect of conventional residue incorporation practiced by farmers was assessed in detail to encourage farmers opt for informed choices and also to encourage both environmentally and economically sustainable systems-thinking

Environmental impact assessment of wheat straw based alkyl polyglucosides produced using novel chemical approaches

This paper evaluates and quantifies the environmental performance of alkyl polyglucosides sourced from wheat straw (WS-APG), a low-cost and low-ecological impact agricultural residue, compared to that of their commercial counterpart, which is sourced from palm kernel oil and wheat grain (PW-APG). Escalating pressure to consider the environmental sustainability of fossil derived surfactant consumption has driven biosurfactants to become the product of choice within the surfactant market, and a class of ‘plant’ based non-ionic surfactants called alkyl polyglucosides (APG) are particularly prevalent. However, the existing food based feedstock of APG such as coconut oil, palm oil, wheat and corn (in addition to being expensive) will potentially undermine the claimed ‘sustainability’ of the APG products (i.e. the ‘food vs. chemical’ issue). Here, we present the “cradle-to-gate” life cycle impact assessment of a suggested alternative, hybridised APG synthesis technique where the Fisher glycosidation method is supplemented by novel, green chemistry based techniques. This evaluation provides a quantitative insight into direct GHG intensity and other ecological impact indicators, including land use, waste generation and energy consumption. Upon evaluation, the wheat straw-derived pathway delivered GHG-emission savings in the range of 84–98%, compared to that of the palm kernel–wheat grain pathway. Waste generated from the production of unit mass of the product amounted to 0.43 kg and 10.73 kg per kg of WS-APG and PW-APG, respectively. In addition to the above mentioned facts, the ‘cradle–gate’ stages of WS-APG production were also found to consume relatively lower amounts of water and fossil-derived energy. In conclusion, of the two APG production pathways, the suggested ‘hybrid’ pathway using an agricultural residue, wheat straw, was found to be sustainable and to demonstrate better environmental performance