Bioethanol Production from Oil Palm Empty Fruit Bunches Using Saccharomyces cerevisiae Immobilized on Sodium Alginate Beads

Bioethanol is an environmentally benign renewable energy commonly obtained from glucose fermentation using Saccharomyces cerevisiae. The purposes of this study are to investigate the effects of time, temperature, pH, immobilized yeast cell loading, beads reuse during ethanol production through batch fermentation of glucose derived from oil palm empty fruit bunches by S. cerevisiae immobilized on Na-alginate beads and to compare the performance of fermentation using immobilized yeast cells and that of using a free cell system. The results revealed that time, temperature, pH, yeast mass and beads reuse significantly affected the ethanol and final glucose concentrations. As expected, a maximum ethanol concentration was obtained from fermentation using immobilized yeast cells at 30 °C, pH 5, and immobilized yeast cell loading of 0.75 g for 48 hours. However, fermentation with a free cell system at the same conditions resulted in lower ethanol yield. The highest ethanol concentration of 88.125 g/L with a productivity of 1.84 g/L·h was achieved from the second cycle fermentation using of immobilized cells beads. The results suggest that an immobilized cell system exhibits great potential applications for improved ethanol production due to its ability to sustain the stability of cell activity, reduce contamination tendency, and protect yeast cells from any possible inhibitions

Diversifikasi Olahan Susu Sapi Segar Menjadi Produk Kefir untuk Minuman Probiotik dan Masker Wajah di Kelurahan Plalangan Gunungpati Semarang

Plalangan Village is one of the villages that produce fresh cow's milk in the administrative area of Gunungpati District, Semarang City, Central Java Province. The average daily activity of residents of Terwidi Village RT02 RW04, Plalangan Village, Gunungpati District, Semarang City in particular is raising cattle. The number of cattle breeders is 40 people who are members of the Ngudi Rahayu Terwidi Dairy Cattle Group (KTSP). The current number of cows is 75 heads, much lower than 5 years ago. The decline in the number of cows is due to the fact that they think that a dairy business that only relies on dairy products does not provide a steady income. Even though there is a lot of potential that can be developed from the dairy cattle business, including the diversification of dairy products. Kefir is a heterofermentative fermented product that has a taste, color and texture that resembles yogurt and has a distinctive aroma like tape. Kefir products circulating in the community today are not only consumed as probiotic drinks but can also be used as cosmetic products, such as masks. The main program will be carried out by the Community Service (PKM) team by empowering dairy cattle businesses through diversification of fresh cow's milk products to become high-value products, namely kefir which can be used as probiotic drinks and face masks

PELATIHAN APLIKASI TURNITIN DAN MENDELEY SOFTWARE BAGI MAHASISWA UNNES DALAM RANGKA PENINGKAATAN KOMPETENSI

Di dalam dunia akademik, akademisi tidak pernah lepas dari budaya menulis artikel ilmiah. Baik penulisan artikel untuk mengikuti suatu lomba, memenuhi tugas kuliah, menulis laporan penelitian hingga artikel untuk dipublikasikan pada jurnal baik nasional maupun internasional. Permasalahan utama yang dialami penulis serta mitra dalam menuliskan artikel ilmiah adalah masalah orisinalitas, praktik plagiarisme serta penyusunan refrensi. Plagiarisme merupakan salah satu tindak pidana yang mengambil, menerbitkan atau menyatakan sebagai milik sendiri dari orang lain, dalam hal ini hasil dari suatu pemikiran sang pencipta. Praktik plagiarisme dalam penulisan tugas, karya ilmiah, skripsi maupun disertasi masih banyak kita jumpai di kalangan akademisi, baik mahasiswa, guru maupun dosen. Sebelum kegiatan sosialisasi, dilakukan observasi untuk mengetahui tingkat pengetahuan yang dimiliki oleh para peserta tentang penulisan artikel terutama mengenai plagiasi dan penyusunan refrensi. Metode yang dilakukan adalah tanya jawab. Hampir 90% peserta belum mengetahui cara menggunakan Turnitin dan Mendeley dalam penulisan jurnal. Hasil kuisioner mahasiswa sangat puas dengan adanya pelatihan Turnitin dan Mendeley

Comparative Study on the Various Hydrolysis and Fermentation Methods of Chlorella vulgaris Biomass for the Production of Bioethanol

One of the microalgae that can be potentially used to produce bioethanol is Chlorella vulgaris, as it is rich in carbohydrates. However, the carbohydrates in C. vulgaris cannot be converted directly into ethanol. This study aimed to investigate the chemical and enzymatic hydrolysis of C. vulgaris, which is subsequently followed by fermentation. The catalysts used in the chemical hydrolysis were hydrochloric acid, sodium hydroxide, and potassium hydroxide, while the enzymes used were the mixture of alpha-amylase + glucoamylase, alpha-amylase + cellulase, and alpha-amylase + glucoamylase + cellulase. The hydrolysate obtained from chemical hydrolysis was fermented through Separate Hydrolysis Fermentation (SHF), while the one from enzymatic hydrolysis was fermented through Simultaneous Saccharification and Fermentation (SSF), in which both processes used S. cerevisiae. After undergoing five hours of enzymatic hydrolysis (using alpha-amylase + glucoamylase), the maximum glucose concentration obtained was 9.24 ± 0.240 g/L or yield of 81.39%.  At the same time and conditions of the substrate on chemical hydrolysis, glucose concentration was obtained up to 9.23 + 0.218 g/L with a yield of 73.39% using 1 M hydrochloric acid. These results indicate that chemical hydrolysis is less effective compared to enzymatic hydrolysis. Furthermore, after 48 hours of fermentation, the ethanol produced from SHF and SSF fermentation methods were 4.42 and 4.67 g/L, respectively, implying that producing bioethanol using the SSF is more effective than the SHF method