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A study of batch fermentation of green algae (Spirogyra majuscula Kuetz) from Pengging Lake, Boyolali, Central Java for bioethanol source using immobilization technique of Ca-alginate for Saccaromyces cerevisiae entrapment has been done. The scope of the study emphasized on the best condition for the processes of hydrolysis and fermentation. Concentration of sulfuric acid and hydrolysis time were varied with 0.1, 0.2, 0.3, 0.4 and 0.5 M for 30, 90, 150, 210, 270, 330, 360, 390, 420, and 450 min to obtain the maximum glucose content of UV analysis. Na-alginate : yeast ratio and fermentation time were varied with 1:5, 2:4, 3:3, 4:2 and 5:1 (w/w) for 1, 2, 3, 4, 5, 6 and 7 days. Distillation at 70-80 °C was deployed to purify the fermentation product. The ethanol content in the product was analyzed using gas chromatography-flame ionization detector (GC-FID). The result of study showed that maximum glucose content was obtained 2.1% from 0.2 M sulfuric acid for 6 h of hydrolysis. Maximum ethanol content was obtained 54.1% from 2:4 ratio of Na-alginate : yeast (w/w) for 4 days of fermentation. The study also concludes that immobilization technique of Ca-alginate increase alcohol content compared to without immobilization of green-algae fermentation.

Polybutylene itaconate (PBI) for modification with divinyl benzene (DVB) and glycerol has been synthesized at 180 °C for 3 h via polycondensation of itaconic acid (IA) and butanediols using catalyst of Ti(OBu)4. Modification on PBI was done with addition of 15%, 20% and 25% DVB (w/w) using benzoyl peroxide. With glycerol, weight variations of glycerol:1,4-butanediol (BDO) in the synthesis were 10%, 30%, and 50% (mole/mole). PBI and PBI modified with DVB and glycerol were characterized with FTIR and TG-DTA. PBI showed a wavenumber shift from 1703 cm-1 to 1728 cm-1 of the C=O functional group from acid to esther. The DVB modification on PBI also showed that the intensity decrease of C=C stretching was due to the formation of crosslinking on the double bond. In the modification with glycerol, three dimensional networking on the polyester occurred through bonding between hydroxyl of glycerol and acid group of IA. Constant intensity of C=C stretching on polyester was seen. The thermal stability of PBI modified with DVB increased, accompanied by rigidity change of the structure. The thermal stability of PBI modified with glycerol decreased, caused by the decrease of regularity degree and the elasticity increase of the three dimensional structure of polyester.