Study On Solid State Fermentation Of Plant Meal By Lactobacillus

The lack of protein feeds, competitive contradiction between grain for human and feed grain, and others restrict the development of China animal husbandry. Making the best of the industrial and agricultural leftovers and unusual feedstuffs including soybean meal, peanut meal, rapeseed meal, bran, etc. becomes a way to solve the shortage of feed grains of China at present. However, the unusual feedstuffs have adverse factors such as low digestive utilization ratio, poor organoleptic quality and existing hazardous and noxious substance, which affect the widespread promotion and use. Microbial solid fermentation can eliminate the adverse factors of unusual feedstuffs and meanwhile improve the protein content in feed and perfect the nutritional quality of feeds. So, the intensive study on technology of microbial solid fermentation of plant proteins can effectively improve the utilization rate of protein feed and guarantee the safety of meet products. This paper, taking the Lactobacillus as main study bacteria, studies and screens the bacteria for feed by Lactobacillus fermentation, fermentation conditions and effects on quality of different plant protein feeds. Main results and conclusions are as follows:1.Screening of good Lactobacillus: take the soybean meal as main substrate for solid-state fermentation, study and compare the total acid content, acid-soluble protein content and viable count of Lactobacillus in substrates inoculated with Lactobacillus casei GL-3, Lactobacillus fermenti FL18, Lactobacillus acidophilus SL32-7 and Streptococcus thermophiles ST20 after anaerobic fermentation. The results show that: under the condition of viable count of GL-3 of 245 million /g, the acid-soluble protein content in fermented soybean meal reaches 8.66% and the lactic acid content reaches 4.64%, and fermented soybean meal has aromatic smell and moderate acidity, is golden yellow and has no mildew. So, GL-3 is good bacterial strain for feed by lactobacillus fermentation.2. Optimization of fermentation conditions of Lactobacillus casei GL-3: The glucose, beef extract and magnesium sulfate are important impact factors obtained through Placett-Burman design on base of MRS formula, the response surface experiment on three factors is carried out, and the final optimum medium formula is confirmed, namely, the glucose of 20 g/L, beef extract of 10 g/L, magnesium sulfate of 0.08 g/L, manganese sulfate of 0.2 g/L, dipotassium phosphate of 4 g/L, peptone of 15 g/L, yeast extract of 5 g/L, ammonium citrate of 2 g/L, and Tween 80 of 1 g/L. We have studied the culture conditions of Lactobacillus casei GL-3 by single-factor experiment, taking the viable count as the index, we have confirmed that the optimum culture time is 24 h, the optimum inoculation amount is 1.0%, the optimum culture temperature is 37℃, and the additive amount of calcium carbonate is 1%.3. Effect of Lactobacillus casei GL-3 on quality of solid-state fermentation of various plant-based meals: the GL-3 after optimized culture is used as starter culture and applied to the soy bean meal, guar meal, peanut meal and rapeseed meal for fermentation. After the anaerobic solid-state fermentation, compared with unfermented materials, their total acid contents are increased by 510%, 370%, 1,050% and 120% respectively; small peptide contents are increased by 510%, 240%, 280% and 70% respectively; the free amino acid contents are increased by 280%, 480%, 390% and 250% respectively. Compared with unfermented meals, all fermented meals smell the fermented fragrance and sour, besides, no mildew is produced and the overall feeding feature is also improved.