Abstract

Background:
Indonesia has a high production of cassava, and cassava waste has significant potential as an alternative feed. However, the high levels of hydrogen cyanide (HCN) and crude fiber in cassava waste pose safety risks for its use as animal feed.

Aim:
This study aimed to identify the morphology and molecular characteristics of cyanolytic and cellulolytic bacteria from cassava waste and evaluate their potential in reducing cyanide levels and improving its nutritional value to ensure feed safety.

Methods:
The first step of this research involved the isolation and screening of cyanolytic and cellulolytic bacteria from cassava waste using DNA sequence homology analysis and constructing a phylogenetic tree. The second step evaluated the potential of the identified bacteria to improve cassava waste as a safe feed. The bacteria were used as inoculants in cassava waste fermentation, employing a factorial, completely randomized design with two factors: types of inoculants and fermentation duration. Data were analyzed using analysis of variance followed by Duncan’s Multiple
Range Test.

Results:
This study identified two novel bacterial strains, namely Proteus vulgaris HT3, and Citrobacter freundii HT1. The application of these bacteria as inoculants in cassava waste fermentation at different durations significantly reduced cyanide content, crude fiber, and pH, while significantly increasing protein content. This improved the quality of cassava feed as a safe feed.

Conclusion:
Cassava waste fermented for 15 days with C. freundii HT1 produced the best feed quality and safety, with the lowest HCN and crude fiber and high crude protein content.

Key words: Cassava waste, Citrobacter freundii HT1, Cyanide reduction, feed safety, Proteus vulgaris HT3