Philippine E-Journals

Identification of Linamarase-Producing Lactic Acid Bacteria and Yeasts for Cassava (Manihot esculenta Crantz) Sourdough Fermentation

Francisco B. Elegado | Margarita A. Mercado | Hazel Alena D. Tan | Johanna A. Bangoy | Ralp Ryana M. Gibas

 

Abstract:

Cassava (Manihot esculenta Crantz) is a tropical root crop considered a staple food to millions of people worldwide. However, one of the drawbacks of this root crop is the presence of toxic cyanogenic compounds used by the plant as a defense mechanism against pests. Fortunately, the toxic compound can be degraded during fermentation, facilitated by linamarase which is a hydrolytic enzyme for cyanide degradation and can be produced by lactic acid bacteria (LAB) and yeasts. Thus, this project aimed to screen LAB and yeasts for their ability to produce linamarase which can then be utilized for cassava sourdough fermentation. Previously, we have screened a total of 166 LAB from an existing collection of cultures and from cassava sourdough, and 113 yeast isolates from the forest canopy for their ability to degrade cyanide. To ensure that the isolates are safe to be used for the fermentation of cassava sourdough, the isolates were identified through 16S and 18S rRNA sequencing. The high linamarase-producing LAB isolates were that from papaya flower, identified as Enterococcus faecalis, and that from cassava sourdough, identified as Leuconostoc mesenteroides. Moreover, the three yeast isolates with high linamarase activity were identified as Cyberlindnera mrakii. The HCN degrading abilities of these isolates were characterized during sourdough and bread preparation.