Degradation of Cell Wall Materials from Sweetpotato, Cassava, and Potato by a Bacterial Protopectinase and Terminal Sugar Analysis of the Resulting Solubilized Products.

Abstract

Cell wall materials (CWMs) from sweetpotato, cassava, and potato starch residues were degraded using a crude enzyme solution from the culture filtrate of a Bacillus sp. isolated from soil, Bacillus sp. M4. This organism has been found to secrete polygalacturonic acid lyase (PGL) and glycan depolymerase activities, especially arabinanase, but cellulase activity was nearly absent. Sugar analysis of the solubilized product after enzyme treatment at pH 7.0 revealed that it is mainly composed of galacturonic acid, galactose, and arabinose, the sugars found commonly in the pectin fraction. This suggested the presence of a protopectinase (PPase) activity in the culture filtrate. The presence of EDTA completely inhibited PGL but PPase activity was almost retained, suggesting that the PGL is not the primary activity responsible for pectin solubilization. The mode of action of the crude enzyme was determined by terminal sugar analysis using HPAEC-PAD after hydrolysis of the reduced products. Results revealed that galactose is the main neutral sugar at the reducing terminal of the products, although rhamnose was also present in the higher molecular weight component. This suggested that at neutral pH, the primary activity in the culture filtrate of Bacillus sp. M4 is a B-type PPase, which attacked the galactan as well as rhamnogalacturonan moieties of the protopectin, resulting in the release of a soluble pectin fraction.

Simultaneous utilization of non-starch polysaccharides and starch and viscosity reduction for bioethanol fermentation from fresh Canna edulis Ker. tubers

“…Therefore, the release of more mannose and glucose in this present study may indicate that, after treatment with acid xylanase, hemicelluloses were partly hydrolyzed, exposing the recalcitrant cellulose to b-glucanase attack. The result is similar to that obtained by Salvador et al (2002) who reported that more soluble sugar could be liberated by adding protopectinase. Srichuwong et al (2009) also reported that reducing sugar was liberated after potato mash was treated with three kinds of commercial CWDEs (Celluclast 1.5 L, Pectinex Ultra SP-L and Viscozyme L).…”

Cassava Pulp as a Biofuel Feedstock of an Enzymatic Hydrolysis Proces

“…This supported that hemicelluloses and pectin of cassava pulp is rich in galactan [15]. In this study, the tapioca industry probably employed either higher starch or lower fiber portion of an earlier-matured cassava cultivar.…”

“…Glucans were the major polysaccharide [8] while major monosaccharide of the cassava a pulp analysis was galactose (78%), and successively followed by arabinose (10.7%), rhamnose (6.2%), glucose (5.1%), xylose (2.5%), fuccose (0.7%) [15]. Arabinose, xylose, rhamnose, galactose and fuccose composed approximately 7.16% of dry matter, which could be mainly derived from hemicelluloses (2.8±0.1%) and pectin (12.4%) fractions.…”

Development of starter culture for improved processing of Lafun, an African fermented cassava food product

“…The microbial species most often reported as involved in cassava root softening are Bacillus spp. (Okafor et al 1984; Amoa-Awua and Jakobsen 1995; Salvador et al 2002;Mante et al 2003;Coulin et al 2006). Amoa-Awua and Jakobsen (1995) reported that Bacillus spp.…”