Trends in the biomanufacture of polyhydroxyalkanoates with focus on downstream processing.

The aim of the current review is to analyze trends in development of an efficient technology for polyhydroxyalkanoate (PHA) biomanufacture highlighting the up-to-date progress on PHA biosynthesis and focusing on the downstream processing. Three main production pathways were identified: through microbial, enzymic, or plant routes. Microbial fermentation processes were predominant, with a wide range of microorganisms, starting materials and culture conditions reported. Largely, two schemes for recovering PHAs from the reaction medium post fermentation were identified: dissolving biomass to separate PHAs granules with strong oxidants, and extracting PHAs directly from the biomass using suitable solvents. For the valuable industrial scale biosynthesis of PHA several technological elements need to be applied such as robust whole-cell microbial catalyst with its optimal culturing conditions, suitable carbon source, proper mode of process operation, as well as economical and ecological purification methods.

Enhancement of methane production from co-digestion of chicken manure with agricultural wastes.

The potential for methane production from semi-solid chicken manure (CM) and mixture of agricultural wastes (AWS) in a co-digestion process has been experimentally evaluated at thermophilic and mesophilic temperatures. To the best of author(')s knowledge, it is the first time that CM is co-digested with mixture of AWS consisting of coconut waste, cassava waste, and coffee grounds. Two types of anaerobic digestion processes (AD process) were used, process 1 (P1) using fresh CM (FCM) and process 2 (P2) using treated CM (TCM), ammonia stripped CM, were conducted. Methane production in P1 was increased by 93% and 50% compared to control (no AWS added) with maximum methane production of 502 and 506 mL g(-1)VS obtained at 55°C and 35°C, respectively. Additionally, 42% increase in methane production was observed with maximum volume of 695 mL g(-1)VS comparing P2 test with P2 control under 55°C. Ammonia accumulation was reduced by 39% and 32% in P1 and P2 tests.

Processing of food wastes.

Every year almost 45 billion kg of fresh vegetables, fruits, milk, and grain products is lost to waste in the United States. According to the EPA, the disposal of this costs approximately $1 billion. In the United Kingdom, 20 million ton of food waste is produced annually. Every tonne of food waste means 4.5 ton of CO(2) emissions. The food wastes are generated largely by the fruit-and-vegetable/olive oil, fermentation, dairy, meat, and seafood industries. The aim of this chapter is to emphasize existing trends in the food waste processing technologies during the last 15 years. The chapter consists of three major parts, which distinguish recovery of added-value products (the upgrading concept), the food waste treatment technologies as well as the food chain management for sustainable food system development. The aim of the final part is to summarize recent research on user-oriented innovation in the food sector, emphasizing on circular structure of a sustainable economy.

Use of immobilised biocatalysts in the processing of cheese whey.

Food processing industry operations need to comply with increasingly more stringent environmental regulations related to the disposal or utilisation of by-products and wastes. These include growing restrictions on land spraying with agro-industrial wastes, and on disposal within landfill operations, and the requirements to produce end products that are stabilised and hygienic. Much of the material generated as wastes by the dairy processing industries contains components that could be utilised as substrates and nutrients in a variety of microbial/enzymatic processes, to give rise to added-value products. A good example of a waste that has received considerable attention as a source of added-value products is cheese whey. The carbohydrate reservoir of lactose (4-5%) in whey and the presence of other essential nutrients make it a good natural medium for the growth of microorganisms and a potential substrate for bioprocessing through microbial fermentation. Immobilised cell and enzyme technology has also been applied to whey bioconversion processes to improve the economics of such processes. This review focuses upon the elaboration of a range of immobilisation techniques that have been applied to produce valuable whey-based products. A comprehensive literature survey is also provided to illustrate numerous immobilisation procedures with particular emphasis upon lactose hydrolysis, and ethanol and lactic acid production using immobilised biocatalysts.