Amplicon metagenomic analysis of bacterial and fungal communities associated with commercial tempeh.

This study investigated the role of product type and fermentation time point on the community composition of tempeh produced in a commercial facility in the United States of America. Product levels were 'soy' and 'multigrain'; time points levels were 'pre-inoculation', 'post-inoculation' (after commercial stater was added to raw materials), 'early' (~5 h), 'middle' (~10-15 h), 'end' (~20 h), and 'packaged' (the packaged finished product. Soy tempeh was made from just soy, whereas multigrain tempeh was made from soybeans, brown rice, millet, kasha, and quinoa. A 2 step PCR was conducted to prepare samples for sequencing. Due to low biomass of several pre-inoculation and post-inoculation samples, some samples were subject to 35 instead of 25 rounds of PCR; amplification batch 1 = 25 rounds, amplification batch 2 = 35 rounds.