A method of and a system for digesting grain based protein and fiber materials using enzymes. The grain based protein and fiber materials can be found in whole stillage in an alcohol production. The method and system produces more digestible proteins, more soluble proteins, soluble protein fractions, peptides and amino acids for ruminant and monogastric species compared to the convention methods and systems. In some embodiments, digested fibers are used as absorber and protectant for probiotic culture absorbed in the enriched syrup. The digested fibers and the probiotic culture form a stable pellet. In some embodiments, the digested fibers and the probiotic culture is added to all types of animal feed forming an enriched lactic acid feed and live probiotic culture feed supplement for the feed markets. The feed markets includes aquaculture, poultry, swine, cattle, companion animals, and livestock animals.
