One of the benefits of probiotic bacteria is to become a source of protein that can be used as a product in the field of biotechnology with high use value. Proteins derived from bacteria are less widely used compared to animals and fungi. The aim of this study is to analyze the composition of the media and the optimal time for the growth of a consortium of Bacillus cereus bacteria. The experimental method used is a consortium of B. cereus bacteria isolates (5 Strains) six treatments in each B. cereus consortium, namely the addition of a different protein source (eggs and skim milk, the same carbohydrate source, namely Sago) and 3 different concentrations in each protein source (8%, 10%, and 12%) so that the treatment obtained was 6 treatments with 3 replications in each treatment. Measurement of bacterial culture growth was carried out every 6 hours for 24 hours using two methods, namely the TPC method and bacterial cell biomass. Optimal growth was found in sago media which was added in different concentrations, namely 12% due to growth in this medium which was close to the same results as growth in positive control. Growth on biomass measurements showed similar results to the growth pattern similar to TPC. While in milk sago media, the growth is less because the exponential and stationary phases are shorter.

Single-cell protein (SCP) is a protein source produced from single-cell organisms, one of which is bacteria. Bacillus cereus SN7 is a potential isolate from a group of heterotrophic bacteria that has been isolated from the mouth of the Siak River, Riau Province, Indonesia. This study aims to analyze the potential of B. cereus SN7 bacteria using different growth media. The method used is an experimental method using Bacillus cereus SN7 bacterial isolate with different protein sources (eggs and skim milk) at different concentrations (8%, 10%, and 12%). All of treatments used the same carbohydrate source, Sago with 3 replications in each treatment. Measurement of bacterial culture growth was carried out every 6 hours, 12 hours, 18 hours and 24 hours based on the total plate count (TPC) method and bacterial cell biomass. The result show that the most optimal growth potential for Bacillus cereus SN7 bacteria is sago media added with 12% egg white as a protein source. This data have the same results as growth in commercial culture media (control). The growth of Bacillus cereus SN7 isolates in each treatment medium had almost the same growth pattern at the beginning, which experienced an exponential phase at 6 to 12 hours of incubation time. Meanwhile, in milk sago media, the average growth was not very good because the exponential and stationary phases were shorter.

The aim of this research was to determine the optimal media composition and incubation time for the growth of Bacillus cereus and B. cereus isolate consortium with other strains isolate. Using an experimental method, which was testing 2 groups of bacterial isolates; B. cereus strain SN7 (isolate N) and bacterial consortium (combination of 5 isolates of B. cereus with different strains). Each group of isolates was grown in sago waste media added with two different protein sources (egg whites and skim milk) and 3 different concentrations in each protein source (8%, 10%, and 12%) with 3 replications in each treatment. Bacterial culture was measured every 6 hours for 24 hours using three methods; total agar plate count, spectrophotometric methods, and bacterial cell biomass methods. There was no significant difference between the growth of these two groups of bacterial isolates. Optimal growth of each isolate was in the sago waste media which was added with egg white but with different concentrations, namely 10% in B. cereus SN7 and 12% in the consortium. B. cereus consortium showed higher growth than B. cereus SN7. The optimal time for bacteria to grow was in the range of 12 to 24 hours.