Indonesia has various types of tubers offered to be developed, one of which is porang tuber (Amorphophallus muelleri Blume). Amorphophallus muelleri Blume has macronutrient content. Macronutrients consist of carbohydrates, starches, fiber, glucomannan, protein, and lipid. Porang tubers have higher glucomannan content applied in the food sector including emulsifiers and stabilizers based on the application in the pharmaceutical field. This research is a research on the exploitation by fermentation using Lactobacillus bulgaricus bacteria. Porang tuber fermentation (Amorphophallus muelleri Blume) with Lactobacillus bulgaricus bacteria contains carbohydrates, starch, fiber, glucomannan, protein, and lipid. Macronutrient levels were tested in accordance with SNI (National Standard of Indonesia) 1992. The results of the research on macronutrient content before fermentation and after fermentation for 8 hours, 10 hours and 12 hours for carbohydrates were mean ±SD 3.80; starch mean ±SD 2.83; fiber mean ±SD 2.07 ; glucomannan mean ±SD 12.77; protein mean ±SD 2.41; and Lipid mean ±SD 1.89.