A new cyclodepsipeptide, isarin (1), was isolated from the insect pathogenic fungus Isaria japonica Yasuda, together with one known compound, beauveriolide I (2). The structure of this new compound was characterized using a combination of spectroscopic and spectrometric analyses.
The effects of different physical and technological parameter such as time, substrate to liquid ratio, enzyme concentration, temperature, and pH on enzymatic saccharification of alkaline pretreated straw cellulose were studied. For alkaline pretreatment, the straw was incubated with 10 % NaOH at ratio 1:20 (w/v) at 90 °C for 1 hour. After the alkaline pretreatment the cellulose content increased from 50.2 % (w/w) to 67.3 % (w/w). Enzyme used for saccharification of treated and untreated straw was produced from Cellulosimicrobium sp MP1 which was isolated from termite gut. Results from research showed that the highest percentage of saccharification of alkaline pretreated straw was 69.91 %, corresponding to 10.58 mg/mL of reducing sugar. The hydrolysis conditions for reaching this highest saccharification yield were: temperature of 55 ºC, substrate to liquid ratio of 2 g/100 mL, enzyme concentration of 37.5 U/g, pH of 5.5 and hydrolysis time of 48 hours.
The Bacillus sp. strain G4 isolated from termites gut can produce cellulase with high activity in rice bran medium after 72 h of incubation at 37 °C. The crude enzymewas collected by centrifugation at 6,000 rpmfor 15 minutes. The precipitation of cellulasewith ammonium sulfate 60 -90 % saturation and acetone at the concentration 60 % -90 % was studied. Results showed that ammonium sulfate 90 % saturation gave cellulase with highest purification factor 8.87 but the yield was only 59.9 %, whereas acetone at 90 % concentration gave highest yield 83.57 % with purification factor 4.38. CMCase activity of cellulasepreparation obtained by acetone precipitation at 90 % was optimum at pH 7 and 60 °C. Furthermore, CMCase was stable at pH 6.0 -7.0 and at temperature lower than 50 °C.
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