Application of an alkaline and thermostable polygalacturonase from Bacillus sp MG-cp-2 in degumming of ramie (Boehmeria nivea) and sunn hemp (Crotalaria juncea) bast fibres

An alkaline (optimum pH 10.0) and thermo stable (optimum temperature 60 deg reesC) polygalacturonase from Bacillus sp. MG-cp-2 has been applied for the degumming of ramie (Boehmeria nivea) and sunn hemp (Crotalaria juncea) bas t fibres in comparison to the conventional chemical degumming process. Sunn is an East Indian plant with a valuable fibre resembling hemp and lighter and stronger than jute. Of the three treatments i.e, enzymic, chemical. and 'chemical + enzyme' the third treatment was most promising for degumming. The maximum reducing sugar released from the ramie and sunn hemp fibre were 9.4 and 7.6 mu mol/ml, respectively, whereas the percent reduction in the fibre weight of ramie and sunn hemp fibre were 37 and 56%. respectively, af ter 11 h of treatment with chemical and enzyme. The scanning electron micro scopic studies also revealed a complete removal of non-cellulosic gummy mat erial from the surface of ramie and sunn hemp fibres. On the basis of this study, it is recommended that a mild chemical treatment of plant fibre is n ecessary before its enzymic treatment, since neither chemical nor enzymic t reatment is sufficient. (C) 2001 Elsevier Science Ltd. All rights reserved.