ABSTRACT
Microorganisms with efficient organic matter degradation ability are essential for organic waste treatment. In this study, a thermophilic bacterium, Bacillus thermoliquefaciens, was identified to have excellent cellulase, amylase, and protease activity, and provided efficient degradation of food waste. This is the first report on the organic matter degradation potential of B. thermoliquefaciens. Using a "one-variable-at-a-time" approach and response surface methodology, the optimal culture conditions for B. thermoliquefaciens were determined to be a 5% inoculation level, 50 °C culture temperature, 25 mL filling volumes in 250 mL flasks, and 180 rpm shaking for 24 h. The optimized medium was formulated as 1 g Na2HPO4, 1 g KH2PO4, 0.05 g MgSO4, 3 g NaCl, 0.05 g CaCl2, 11.44 g wheat bran powder, 4.92 g soybean meal, and 1 L distilled water at pH 7.12. The maximum biomass attained was 1.57 ± 0.153 × 109 CFU/mL. The cost of this medium was 4.18 times less than that before optimization. This promising result lays a foundation for future industrial application of this bacterium to the degradation of organic waste.
Subject(s)
Bacillus/growth & development , Culture Media/chemistry , Food , Refuse Disposal/methods , Solid Waste , Bacillus/metabolism , Biodegradation, Environmental , Biomass , Cost-Benefit Analysis , Geobacillus stearothermophilus , Hydrogen-Ion Concentration , TemperatureABSTRACT
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ABSTRACT
Tight gas sandstone samples are imaged at high resolution industrial X-ray computed tomography (ICT) systems to provide a three-dimensional quantitative characterization of the fracture geometries. Fracture networks are quantitatively analyzed using a combination of 2-D slice analysis and 3-D visualization and counting. The core samples are firstly scanned to produce grayscale slices, and the corresponding fracture area, length, aperture and fracture porosity as well as fracture density were measured. Then the 2-D slices were stacked to create a complete 3-D image using volume-rendering software. The open fractures (vug) are colored cyan whereas the calcite-filled fractures (high density objects) are colored magenta. The surface area and volume of both open fractures and high density fractures are calculated by 3-D counting. Then the fracture porosity and fracture aperture are estimated by 3-D counting. The fracture porosity and aperture from ICT analysis performed at atmospheric pressure are higher than those calculated from image logs at reservoir conditions. At last, the fracture connectivity is determined through comparison of fracture parameters with permeability. Distribution of fracture density and fracture aperture determines the permeability and producibility of tight gas sandstones. ICT has the advantage of performing three dimensional fracture imaging in a non-destructive way.
