In this research, shrimp waste was fermented with 3 species of symbiotic lactic acid bacteria, namely Streptococcus thermophilus, Lactobacillus acidophilus and Lactobacillus bulgaricus. The ingredient changes occurring in the fermentation process were investigated. Results showed that the production of lactic acid in the fermentation process was remarkably improved, with the pH decreasing rapidly to 4.25 within 8 h, the lowest pH reaching 3.22, and the titratable acidity reaching 25.0 mmol/100ml. The improved acidic environment promoted the removal of calcium and protein, with 91.3% calcium, 97.7% protein and 32.3% carotenoid removed from shrimp waste after 168 h fermentation. The putrefaction was effectively prevented and the TVBN level was low throughout the whole process. Glucose was consumed rapidly in the earlier phase of the fermentation; about 69.4% glucose was consumed in the initial 24 h. The consumption of glucose was in well accordance with the growth of lactic acid bacteria, the removal of calcium and the increasing of titratable acidity. The amino nitrogen content kept increasing within 48 h, thereafter it came to decrease. 88.4% of peptides in the hydrolysate ranged between 1000 ~ 10000 Da, 10.2% smaller than 1000 Da, and 3.44% larger than 10000 Da.
Biological silage of shrimp waste fermented with lactic acid bacteria: Use as a biofertilizer in pasture crops and as feed for backyard pigs
