Changes in caffeine of fermented Liberica coffee beans cv. Liberoid Meranti on roasting levels

One of the varieties of Liberica coffee in Indonesia is the Liberoid Meranti coffee. Fermentation technology and the roasting temperature of Liberica coffee are needed in changing the composition of caffeine in coffee beans. The aim of this research was to see the caffeine content of the Liberica coffee beans cv. Liberoid Meranti fermented by hydrolytic bacteria on levels at a light, medium, and dark roasting temperatures. Coffee fermentation was carried out using the wet processing method and a roasting temperature of 150oC, 175oC, 200oC, and caffeine analysis was carried out by UV-Visible spectrophotometry. The data obtained from each parameter based on roasting levels were processed using the statistical application of Minitab version 16 for Windows and analyzed using ANOVA with a level of 5%. If there is a significant difference from the F-test result (p<0.05), then proceed with the post hoc test. The results showed that all samples contain large amounts of caffeine with various concentrations. The level concentration of caffeine in light roast samples in the range of 10,80 ppm-12,52 ppm, medium roast samples in the range of 11,46 ppm-14,08 ppm, and dark roast samples in the range of 14,49 ppm-16,94 ppm. The caffeine content in fermented Liberica coffee bean experienced a significant difference. The fermentation and roasting process of coffee beans is a complex compound process that can cause changes in caffeine levels.

Enhancement of Substrate Decomposition through Potential Hydrolytic Bacteria for Cumulative Biogas Production

Scenarios focus on the practical behavior of anaerobic decomposition systems to enhance biogas production, in addition to assure economic progression and ecological sustainability. The present study has framed to identify the potential hydrolytic bacteria from five different sources since principally the efficacy of hydrolytic bacteria determines the rate of hydrolysis of anaerobic decomposition and thereby biogas production. Among the 40 dominant bacteria isolated from diverse bases, 10 isolates were selected as efficient through preliminary screening. Consequently, the premier enzyme activity obtained from the isolate G5 obtained from goat rumen fluid for cellulase (44.16±1.00 U/ml), protease (260.63±1.35 U/ml) and lipase (33.20 ± 0.81 U/ml). Morphological, biochemical and molecular characterization revealed that G5 is Bacillus sp. DDG5 (KM093856.1). A range of pH (7.0-7.5) and temperature (40oC) was sufficient for the highest activity of hydrolytic enzymes experienced. Biogas production using cow dung showed an improved efficiency of 9.54 % in Bacillus sp. DDG5 treated tank (70.16 ± 1.54 %) in contrast to control (58.13 ± 1.02%) at 30th day. However, this study established that Bacillus sp. DDG5 obtained from goat rumen fluid is the promising hydrolytic bacteria, since it can be applied for proficient hydrolysis of various organic materials to enhance methane production in outlook. Int. J. Appl. Sci. Biotechnol. Vol 6(4): 386-396

Effect of Acid-Alkaline and Thermal Pre-treatment to Cassava Pulp Feed for Batch Reactors in Optimization of Bio-Methane Yield

Cassava starch mills in Nakhon Ratchasimaprovince operate biogas plants to generate renewable energy from surplus cassava pulp using anaerobic digestion (AD) technologies. However, the biogas yields fluctuate and digestion failure occurs due to suboptimal digester configuration and lack of understanding of the specific properties of cassava pulp substrate. This study used acid-alkaline and thermal pre-treatment to modify the cassava pulp substrate to enhance biogas yields. Concentrated 36N sulphuric acid (H2SO4) and 20M sodium hydroxide (NaOH) was chosen as an acid-alkaline pre-treatment to adjust to the required pH for the substrates, and 45 minat 200 ̊C for the thermal pre-treatment. Extreme pH adjusted substrates such as T1, T2, T12 and T13 required both acid and alkali in high volume, and inhibition occurred from both acid and alkali resulting in retardation of fermentation by hydrolytic bacteria, a lower volatile fatty acid to total alkalinity ratio (VFA/TA), more depletion of reducing sugars and a lower bio-methane yield. The results showed Soluble Chemical Oxygen Demand (SCOD) obtained from decomposition of lignocellulosic structure of fresh cassava pulp by combined thermal-chemical pre-treatment, was found highest in T2 which was pre-treated at pH2 having more than 100 g L-1. Though SCOD could be enhanced by acid-alkaline pre-treatment, it led to inhibition driven by radicals of acid and alkaline. Three different mixing ratios, i.e. 3%, 5%, and 10%(w/v) were compared against without pre-treated samples, and found 5%Total Solids (TS)was most suitable after subjected to acid-alkaline pre-treatment and produced biogas yield at 4125.2 mL kg-1TS in batch digestion for 21 d. Pre-treatment was found increase bio-methane by up to a factor of six.