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.

The utilization of biomass as a source of new and renewable energy is being carried out. One of the technologies to convert biomass as an energy source is pyrolysis which is converting biomass into more valuable products, such as bio–oil. Bio–oil is a liquid which produced by steam condensation process from the pyrolysis of coconut shell. The composition of biomass such as hemicellulose, cellulose and lignin will be oxidized to phenol as the main content of the bio–oil. Production of bio–oil from coconut shell was investigated via fast pyrolysis reactor. Fast pyrolysis was carried out at 500 °C with a heating rate of 10 °C and 1 hour holding time at pyrolysis temperature. The Bio-oil chemical composition was investigated using GC–MS. Percentage value of phenol, 2–methoxy phenol, 3–methoxy 1,2–benzenediol, and 2,6–dimethoxy phenol was 45.42%, 13.37%, 10.09%, and 11.72% respectively.

Cow’s milk is very easily damaged because of the content of decomposing bacteria that occurs very quickly, so that the milk becomes inappropriate for consumption. Current technological developments in food sector provide an alternative diversification of milk processing products. One such technology is fermentation of cow’s milk into kefir. The method used in this study is a Completely Randomized Design method (CRD) without any repetition. The raw materials used are cow’s milk, kefir grains with various concentrations, namely 3%, 5% and 7% per 1L kefir, with different fermentation lenght namely 18 hours, 21 hours and 24 hours. Furthermore, the characteristics of lactic acid levels were tested using alkalimetry method, protein content test using the formol method, and the Lactic Acid Bacteria (LAB) test using Man Rogosa Sharpe (MRS) on growing medium. Characteristic test results show that lactic acid levels are optimal at 5% kefir grain concentration as well as optimal protein levels at 5% kefir grain concentration, while total LAB obtained are 1.80 × 107 cells / mL at 3% kefir grain concentration.

Energy is an important parameter in the social and economic development of a country. Thus, it is necessary to seek renewable energy to supply energy needs in Indonesia. The production of bioethanol from microalgae as a biofuel is one way to reduce the use of fossil fuels. Microalgae has an advantage over other types of biomass sources due to its high biomass productivity and do not compete with agricultural crops for land and water resources. In the bioethanol production process, the ethanol and water form an azeotrope mixture of 95.6% of ethanol at 1 atm and 78.15°C. The objective of this research was to analyse and determine the operating conditions and the optimum distillation column configuration which results in high ethanol purity according to fuel specifications (fuel grade ethanol). The method of pressure-swing distillation was applied to separate the azeotrope of ethanol-water and obtain high purity ethanol. A simulation model of bioethanol production with pressure-swing distillation system was conducted by using Aspen Plus V10. In this research, the influence of process parameters such as distillation column pressure, reflux ratio, feed stage location, and the number of theoretical stages was analysed by using model analysis tools. The results showed that the obtained bioethanol purity of 99.9% with the condenser and reboiler duty of the LP column -79.931 kW and 667.651 kW, respectively; while the HP column is -47.627 kW and 57.698 kW.

Corrosion is one of the problems cause the material fail, leaks in the equipment and pipe systems in the industry which caused distrub in productivity of production in industry. There are some ways to prediction erosion in pipes, with the conventional or manual and CFD. CFD is to prediction erosion in turbulent air flows with variations in coal particle size and velocity of flowing air. The results of prediction erotion based on CFD is numerical and graphic, by displayed numerical results into visual results. These results include about the velocity, pressure, and temperature distribution in the air flow. So, CFD can be used to prediction pipe because it has wide coverage and effective in display numerical and visual results. Discreate Phase Model is the model of CFD with a variable stream velocity of 10 m/s, 15 m/s, 20 m/s and a solid loading of 5%, 10%, 15%, 20%, 25%. From the results, the maximum erosion rates increased with increasing sizes of particles and stream velocities. However, the location of the maximum erosion rate in the elbows region was independent on those mentioned parameters.