Production of Bacillus thuringiensis (Bt) var. kurstaki HD-1, an industrially produced biopesticide source, was tested as a potential method to valorize wastewater treatment sludge. The effects of sludge solids concentration and inoculum size were verified on the production of Bt. Inoculum sizes of 1% and 5% were tested. The cell and spore counts achieved were comparable to those in the industry standard. Sludge with 1% (v/v) inoculum size gave higher entomotoxicity compared to that of 5% inoculum. It was observed that sludge samples with lower solids concentration gave marginally lower cell and spore count but gave considerably higher toxicity. The production time was also comparable to the industrial standard. Results from these experiments and their economical implications are discussed in this paper.

The manufacturing of biodiesel has seen some major advances in recent years that attempt to improve environmental performance, sustainability, and efficiency. The research of non-food sources like algae, jatropha, and waste oils has been encouraged by a significant trend called feedstock diversification. Enzymatic and supercritical fluid transesterification are two advanced manufacturing techniques that have showed promise in increasing conversion rates and processing a larger variety of feedstocks. Demand has increased and production has been encouraged by regulatory and blending programmes, such as mandating biodiesel use and blending biodiesel with petroleum fuel. The emphasis now is on sustainability and carbon reduction, with certification programmes ensuring compliance with social and environmental standards.

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