Asian palm civet digestive juices enter into the beans and modify the micro-structural properties of these beans. Proteolytic enzymes cause substantial breakdown of storage proteins. Kopi Luwak is traditionally made from the faeces of wild civets, however, due to it becoming a trendy drink, civets are being increasingly captured from the wild and fed coffee beans to mass-produce this blend. Many of these civets are housed in battery cage systems which have been criticised on animal welfare grounds. The impact of the demand for this fashionable coffee on wild palm civet populations is yet unknown but may constitute a significant threat. In Indonesia,
Metabolic waste excreta. Some mammals including humans excrete uric acid as a component of their urine but it is only a small amount. These compounds form during the catabolism of carbohydrates and lipids in condensation reactions, and in some other metabolic reactions of the amino acids. Oxygen is produced by plants and some bacteria in photosynthesis, while CO is a waste product of all animals and plants. Nitrogen gases are produced by denitrifying bacteria and as a waste product, and bacteria for decaying yield ammonia, as do most invertebrates and vertebrates. Water is the only liquid waste from animals and photosynthesizing plants.