No abstract

Food spoilage leading to food waste and substantial economic losses is a major issue for the food industry. The spoilage is often due to bacterial and fungal contamination in foods. Spores from microorganism pose a great concern since they can survive pasteurization and grow in specific foods. The obj1ectives of this work were to investigate the effect of temperature (T: 80-90°C), soluble solid concentration (11–20°Brix), and spore age (30–60 days) on the log reductions of Eupenicillium javanicum ascospores in pineapple juice. It was also carried out to estimate the first-order kinetic parameters (D and z-values) from the log survivor curves. Increasing the temperature from 80 to 90°C for 10 min increased the spore inactivation in 11°Brix pineapple juice by 6.4 log. For 5-log inactivation, increasing the percentage weight (% wt.) of sucrose from 11°Brix to 20°Brix at 90°C, increased the time needed to inactivate the spores by 2.6 min. Likewise, increasing the age of ascopores from 30 days to 60 days, also increased the time required by 16.7 min. The estimated D-values for 30-days old spores in 11°Brix juices were 19.84 min at 80°C, 4.99 min at 85°C and 1.45 min at 90°C, with z-values of 8.6-8.8°C. The results obtained provide useful data to design and predict pasteurization process targeting E. javanicum ascospores.

Mikroalga Chlorella sp. memanfaatkan nutrien yang terdapat di dalam POME sebagai sumber nutrisi untuk pertumbuhannya. Pada penelitian ini dilakukan penyisihan nutrien yaitu kandungan COD dan Nitrogen Total dengan memanfaatkan POME sebagai medium kultivasi di dalam flat-fotobioreaktor. Imobilisasi sel dilakukan untuk membentuk beads dikarenakan sel Chlorella sp. yang mikroskopis, berat jenis rendah, dan sulit dipisahkan dari medium. Untuk mendapatkan efisiensi penyisihan terbaik dilakukan variasi konsentrasi bead alga di dalam flat-fotobioreaktor sebesar 6, 8, 10, 12, dan 14 beads/mL air limbah serta waktu kontak 0, 1, 3, 5, dan 7 hari. Hasil penelitian menunjukkan efisiensi penyisihan COD dan Nitrogen Total terbaik terdapat pada flat-fotobioreaktor dengan konsentrasi bead alga sebesar 12 beads/mL air limbah pada hari ketujuh sebesar 77,8 % dan 83,5 %.

The ascospores of Talaromyces species can survive pasteurization and grow in high acid fruit juices. In this study, the thermal inactivation of Talaromyces flavus ascospores in pineapple juice was carried out and the log reductions were counted. First, the effect of temperature (T: 80-90°C), soluble solid content (SS: 10-30°Brix), and spore age (30-60 days) on the viability of ascospores were investigated. Then, the first-order kinetic parameters (D and z-values) were determined from the log survivor curves. Results of the thermal processes showed that higher log reductions for higher temperatures (5.2 log for 90°C vs. 0.89 log for 85°C and 0.28 log for 80°C) were obtained at 10°Brix after 15 min heat treatments. Lower spore reductions were observed at higher SS (1.5 log for 30°Brix vs. 2.4 log for 20°Brix and 3.0 log for 12°Brix after 9 min at 90°C). Longer time needed to inactivate the older spores (53.8 min for 30 day-old-spores vs. 67.1 min for 60 day-old-spores). The log survivors are better described by the first-order kinetics at 80-90°C. The estimated D-values in 12°Brix juice were 63.8 min, 16.9 min and 2.89 min for 80, 85 and 90°C, respectively, with z-value of 7.9°C. This result emphasizes the importance of temperature, SS, and ascospore age on the heat resistance of T. flavus ascospores in high acid fruit juice.

Background: The utilization of microalgae as a renewable energy is an important aspect in solving shortage of future oil reserve in 15 years. One of the renewable energy sources is microalgae biodiesel. Palm oil mill effluent (POME) is a wastewater that has a high content of organic materials. These organic materials can be used as growth nutrients for microalgae. Chlorella pyrenoidosa is one of the most potential microalgae used as a raw material for the production of biodiesel since it contains lipids (8%-35%). Methods: Chlorella pyrenoidosa was cultured on the POME medium with concentrations of 0%, 25%, 50%, 75%, and 100%v with addition of synthetic nutrients (urea: TSP) at the ratios of 2:1 ; 1:2 ; 0.5:1 in a 500 mL Erlenmeyer flask, at pH 6-8, aeration using aquarium pumps, and using LED lights (3000 lux). Results: It was revealed that at POME concentration of 25% and with addition of urea: TSP at a ratio of 2:1, the optimum specific growth rate (0.306/day) with the highest number of cells was 3.530 × 107 cells/mL and the highest lipid content was 36% of its dry weight. The removal efficiency of POME could be obtained from the removal efficiency of chemical oxygen demand (COD), total nitrogen, and orthophosphate (P-PO4 ), which was 70, 90.42, and 81.12%, respectively. Conclusion: According to the results, under appropriate culture conditions, C. pyrenoidosa can produce lipids with good use of nutrients contained in the POME medium.

Mikroalga memiliki kandungan lemak (lipid) dan asam lemak (fatty acid) yang dapat dikonversi menjadi salah satu energi alternatif biodiesel. Biodiesel adalah bahan bakar alternatif yang tidak beracun dan dapat terurai secara alami. Kelimpahan dan pertumbuhan mikroalga Chorella sp. yang sangat cepat dinilai ideal dan potensial untuk dijadikan sebagai bahan baku produksi bioenergi. Disisi lain mikroalga membutuhkan nutrisi seperti karbon dan nitrogen untuk pertumbuhannya.

Electroplating industry is one of the industries producing liquid waste containing heavy metals. Among the heavy metals contained in the liquid waste is Chromium (Cr) which has a high toxicity. One technology that can be applied to eliminate Cr metal in liquid waste is by the method Biosorption using biomass derived from yeast bread (Saccharomyces cerevisiae). This study aimed to study the ability of bread yeast biomass (saccharomyces cerevisiae) in removing Cr metal on variations in biosorbent weight of 0.25; 0.5 and 0.75 grams, mesh size 80; 100 and 140 and contact time 1; 2; 3 and 4 hours. The results showed that the highest Cr removing efficiency occurred at 0.75 g biosorbent weight at 80 mesh and 4 hours contact time with efficiency of 54.7%. The biosorption process indicates that the adsorption isotherm type obtained is Langmuir isotherms assumed that the layer formed is monolayer with R2 value of 0.8819. The SEM analysis results show the difference of the morphological shape on the sample surface before and after the biosorption process

Biosurfactants are surfactants that are synthesized by microorganisms using organic materials and have biodegradable properties, making them environmentally friendly. One of the applications of biosurfactants in the recovery of petroleum. This study aims to determine the type of biosurfactant produced by Pseudomonas aeruginosa bacteria using crude palm oil as the main carbon source, to determine the effect of variations in pH and CPO concentration on surface tension reduction and emulsification, and compare the best biosurfactant with surfactant synthesis. The production of biosurfactants has  3 stages, namely the bacterial preparation, the biosurfactant production, and the analysis in the form of surface tension, emulsification, crude oil removal, and FTIR. The best biosurfactant was obtained at pH 7 and a carbon source concentration of 3% v/v with surface tension and emulsification values ​​of 42.49 mN/m and 58%, respectively. The pH value and CPO concentration can affect the growth in the biosurfactant production process, thus also affecting the surface tension and emulsification values. The biosurfactants obtained were rhamnolipid biosurfactants. The biosurfactants produced in this study have lower crude oil recovery capabilities than synthetic surfactants with crude oil removal values ​​of 57.78% and 79.34%, respectively.