Hops Biomass

Hops biomass has the ability to reduce Au(III) ions to form Au(0) nanoparticles [65]. XAS techniques have been used to elucidate the average nanoparticle size and to determine the binding and reduction mechanisms of Au(III). These authors 

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Lopez et al. studied the binding and reduction of Au(III) by hop biomass using XAS. The XAS data confirmed the presence of Au(0) in both the native and chemically modified hop biomasses. XANES fittings show that the Au(III) was reduced to Au(0) by approximately 81%, 70%, and 83% on the native, esterified, and hydrolyzed hop biomass, respectively. In addition, the calculation of the particle radius was also in agreement with the results of transmission electron microscopy studies. The average particle could only be calculated for... 

Figu re 12.10 HRTEM image of an irregularly shaped gold nanoparticle formed by the reduction of potassium tetrachloroaurate with a hops biomass, resulting in a tadpole -like shape. 

The most widely available yeast biomass is a by-product of the brewing industry, where the multiplication of yeast during brewing results in a surplus of ceUs. Eor every barrel (117 L) of beer brewed, 0.2—0.3 kg of yeast soHds may be recovered. In the U.S., a substantial fraction is recovered and made available about 40 x 10 kg of brewers yeast aimually. The yeast is recovered from beer by centrifuging and dried on roUer dmms or spray dryers and sold as animal feed or a pet-food supplement. It can be debittered by alkaline extraction to remove the bitter hop residues, and is then sold mainly by the health-food industry. It is available as tablets, powder, or flakes and is often fortified with additional vitamins. Distillers yeast caimot be readily separated from the fermented mash and the mixture is sold as an animal feed supplement. 

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