The potency of cassava starch (var. kristal merah and var. revita) for bio-succinic acid production using indigenous lactic acid bacteria (Leuconostoc sp)

Abstract

Cassava of local strain, a plentiful agricultural product in Indonesia was evaluated for biosuccinic acid production via saccharification and fermentation using indigenous lactic acid bacteria (Leuconostoc sp). Cassava starch is an ideal biosuccinic acid feedstock due to its low price and high sugar content. Conversion of cassava starch into succinic acid is an effort to obtain added-value of the local product. Succinic acid has been well-known as an important platform chemical and being top 12 building block in the chemical industries. In the current study, saccharification of starch was carried out using available glucoamylase enzymes produced by Aspergillus awamori KT 11 (Glutech) in the temperature 60°C and 200 rpm. Results revealed the best yield of total reducing sugar accumulation (62.3 g L−1) was obtained when the ratio of starch solution of var. kristal merah (25% w/v) and glucoamylase was kept to 3:1. HPLC analysis of sugar also showed three different sugar were produced during saccharification: glucose, maltose, and maltotriose. Fermentation of the liquid sugar as a carbon source in various media showed that Leuconostoc sp could produce highest succinic acid in medium SPM, with concentration 3.4 g L−1 in 72 h for var. kristal merah and 3.6 g L−1 g in 48 h for var. revita. The other valuable organic acids, such as lactic acid, citric acid, formic acid, and acetic acid were also formed during fermentation process, with concentration less than 3 g L−1. The results suggested that cassava starch of 2 local strains (var. kristal merah and var. revita) has the potential to be an alternative substrate for efficient and economic valuable organic acids production such as succinic acid.