The production of concrete for construction purposes is a major source of anthropogenic CO2 emissions. One promising avenue towards a more sustainable construction industry is to make use of naturally occurring mineral-microbe interactions, such as microbialinduced carbonate precipitation (MICP), to produce solid materials. In this paper, we present a new process where calcium carbonate in the form of powdered limestone is transformed to a binder material (termed BioZEment) through microbial dissolution and 2 recrystallization. For the dissolution step, a suitable bacterial strain, closely related to Bacillus pumilus, was isolated from soil near a limestone quarry. We show that this strain produces organic acids from glucose, inducing the dissolution of calcium carbonate in an aqueous slurry of powdered limestone. In the second step, the dissolved limestone solution is used as the calcium source for MICP in sand packed syringe moulds. The amounts of acid produced and calcium carbonate dissolved are shown to depend on the amount of available oxygen as well as the degree of mixing. Precipitation is induced through the pH increase caused by the hydrolysis of urea, mediated by the enzyme urease, which is produced in situ by the bacterium Sporosarcina pasteurii DSM33. The degree of successful consolidation of sand by BioZEment was found to depend on both the amount of urea and the amount of glucose available in the dissolution reaction.

Environmentally sound plant treatments that can impose mild physiological stress and elicit bioaccumulation of useful phytochemicals such as kaempferols are limited. We tested ABA foliar application, 100 or 200 µM, and two types of leaf wounding, piercing or hole punching in young greenhouse-grown soy plants. Leaf gas exchange and A/C i response, ΦPSII, pigments and antiradical activity were measured using the same leaf and kaempferols were measured in the leaf above. ABA 200 µM-treated plants had ≥ 20% less gas exchange and 17% less ETR, but greater V cmax and J max compared to control. They had 55% and 100% more stomatal limitation to P net and ΦPSII, respectively, than control. Leaf-wounded plants showed the lowest stomatal limitation to either P net or ΦPSII. Leaf piercing increased chlorophylls 39% and carotenoids 38% compared to control. Six kaempferols quantified were found to be mono-, di-and triglycosides. Each leaf treatment increased total kaempferol yield ranging from 42% in ABA 100 µM to 68% in ABA 200 µM treatment compared to control. In general, kaempferol yields were positively correlated to Pnet in ABA 100 µM-treated plants and to g s in ABA 200 µM-treated plants but negatively correlated to P net in leaf-pierced plants. ABA application and wounding affected the association between photosynthetic primary metabolism and kaempferol accumulation differently. Both ABA application and wounding are promising leaf treatments for eliciting kaempferol accumulation in young soy leaves.