Solid and liquid residues as raw materials for biotechnology

Abstract

In the past few decades huge amounts of solid and paste-like wastes of domestic and industrial origin have been deposited on sanitary landfills worldwide. Only a small proportion was incinerated, where incineration plants were available. Since primary resources, such as ores for metal production or crude oil for the production of gasoline, diesel, solvents and plastics, or coal and natural gas as sources for energy or chemicals are not available in unlimited quantities, and because the deposition of residues, wastes and worn-out commodities on sanitary landfills causes pollution of the atmosphere, the soil and the groundwater due to hazardous gaseous emissions and toxic leachates, wastes from households and from industry must be avoided or minimized at an early stage. Whenever waste material can be recycled it must be re-introduced into production processes and the non-recyclable fractions should be used as a fuel for energy recovery. After incineration, the highly toxic dust fractions of ashes and slags resulting from burning the wastes should be deposited on sanitary landfills, while the granulated mineral slag fractions could be used as a substitute for the sand in cement as a construction material. Here we review various processes for the treatment of organic fractions of differently composed wastes to upgrade them to more valuable, re-usable products or at least to recover their energy content. Upgrading processes of organic wastes include composting, biogas fermentation, production of organic acids and solvents, and biopolymer or biosurfactants production. We also include biological purification procedures for the most important components of wastes, such as chitin from the shells of Crustaceae. Typical examples from pilot-scale or full-scale studies are discussed for each process.

Effects of Liquid Organic Fertilizers on Plant Growth and Rhizosphere Soil Characteristics of Chrysanthemum

“…L1 was derived from shrimp extract, which is the most abundant natural resource on earth, with an estimated chitin yield of 10 10 -10 11 tons per year [22,47]. Additionally, seafood processing wastes do not contain known toxic or carcinogenic materials like liquid wastes from other industries [48].…”

Produção de biossurfactante por levedura

“…Por outro lado, estes custos podem ser significativamente reduzidos pelo uso de fontes alternativas de nutrientes, com baixo custo, bem como através da obtenção de altos rendimentos em produtos. 44 Uma possível solução seria o reaproveitamento de subprodutos industriais como, por exemplo, aqueles provenientes da agroindústria.…”

Influence of Polyphosphate Hydrolysis on the Degradation of Volatile Fatty Acids (VFAs) in Anaerobic Digestion

“…Energy production by anaerobic digestion of animal slurries, sewage sludge, plant residues or wastewater is a major task for a sustainable future development [1]. Digestion connected with biogas production may play a triple part.…”

“…The whole anaerobic digestion process can be influenced by varying factors. It can be differentiated basically according to influences: which are caused by the effects on the enzymatic system of the participating organisms (temperature, pH values, metabolites etc); which are determined by reaction kinetics (mixing, retention time, reactor size etc); which are caused by the composition of the substrate and the intermediate products, especially volatile fatty acids from acidogenesis stage [1].…”