PROTEIN HYDROLYSATES FROM ANIMAL RESIDUES FOR LACTIC ACID FERMENTATIONS: COMPARATIVE STUDY OF DIFFERENT RAW MATERIALS AND METHODS OF HYDROLYSATION

摘要

Growing meat consumption over the past centuries has caused higher amounts of animal by-products. As a consequence of the BSE crisis, established treatments are either not allowed anymore or too expensive. Because of their high protein content, animal by-products, such as animal meals, could be used as low-cost nitrogen sources in fermentation media. Lactic acid has recently gained interest due to its application in poly(lactic acid), a biodegradable biopolymer with promising properties. Before use in fermentation media for lactic acid bacteria, animal meals have to be hydrolysed to increase fermentation efficiency. Blood meal, greaves meal, feather meal and salmon fish meal were hydrolysed under various conditions and subsequently used as a nitrogen source in fermentations with Lactobacillus rhamnosus DSM 20711. Animal meal hydrolysates were shown to be suitable replacements for meat extract and casein peptone in the standard fermentation medium without significantly changing relevant fermentation parameters. The suitability depended on both the raw material and the method of hydrolysis. While hydrolysates of blood meal, greaves meal and salmon fish meal did not cause significant reductions in relevant fermentation parameters compared to fermentations in standard medium, feather meal hydrolysates were not suitable regardless of the hydrolysis method.