การฟอกเยื่อกระดาษแบบชีวภาพโดย Phanerocheate chrysosporuim และ Ganoderma lucidum / เรือนแก้ว ประพฤติ = Biobleaching of a paper pulp by Phanerocheate chrysosporuim and Ganoderma lucidum / Reankeaw Praphet
The biobleaching of a eucalyptus paper pulp with Phanerocheate chrysosporium and Ganoderma lucidum was investigated by using 2 type of media including the PDB with 0.5% glucose and the production medium with 0.4 mM veratyl alcohol. Ten grams of unbleahed eucalyptus pulp (Kappa number 17.47, brightness 36.85%) was added. The conditions tested were at pH 3.0, 4.0, 5.0, 6.0, 7.0 and at temperature 25 ํC, 30 ํC, 35 ํC, 40 ํC, under agitated conditions. Both fungi showed ability to bleach in the production medium. P. chrysosporium preferred initial pH of 5.0, 40 ํC giving 0.274 IU/ml lignin peroxidase, Kappa number 9.53 and Brightness 52.18% within 7 days. G.lucidum preferred pH of 3.0, 25 ํC, giving 0.080 IU/ml lignin peroxidase, Kappa number 12.85 and Brightness 45.54% within 11 days. P. chrysosporium was selected for the crude enzyme by preparation due to its high enzyme activity. The crude enzyme was prepared in the production medium at pH 5.0 with 10g unbleached eucalyptus pulps, and was incubated at 40 ํC 150 rpm for 7 days. The supernatant containing crude enzyme was separated from the pulp by centrifugation at 5,000 rpm for 20 minutes and 4 ํC. The bleaching of the pulp was investigated in the presence of 0.5 mM Sodium citrate buffer at pH 3.0, 4.0, 5.0, 6.0, 7.0 at 25 ํC, 30 ํC, 40 ํC, with 6.25 IU crude enzyme/1 g (OD) pulp. The data showed that the suitable conditions for biobleaching with the crude enzyme are at pH 5.0, 40 ํC giving Kappa number 9.36 and Brightness 50.91% of the eucalyptus pulp.
