Biomass accumulation

Reaction in the simulation begins slowly, but proceeds more rapidly as biomass accumulates, reflecting the reaction s autocatalytic nature. The reaction rate continues to increase until most of the acetate is consumed, at which point it slows abruptly to a near stop. In the simulation, dissolved ferrous iron is present in excess amount. The bisulfide produced as a result of bacterial sulfate reduction reacts with the iron,... 

Fast-growing and high-biomass-accumulating varieties can grow up to 2m in height, and these are suitable for the phytoremediation of salt, heavy metal or both. 

Biomass accumulation and its distribntion are usually determined after a prolonged period of exposure to pollutants. At harvest, the plant is divided into its constitutive organs, the fresh weight of each is recorded and the material is then oven-dried for 1-2 h at 105°C and at 70°C for further 2-3 days, preferably using an air circulation system. Drying time can vary depending on type of tissue. 

The effect of phosphate on alkaloid production has also been evaluated (138). Using a modified induction medium devoid of phosphate and other essential growth factors, production of secondary compounds was more rapid than when phosphate was present. A broader study of the phenomenon has been reported by a French group (139) where, using three alkaloids as markers, the disappearance of the major nutrients from the medium and the evolution of phosphates, nitrates, ammonium ions, glucose, and starch in the cells were observed over time. It was not possible to relate alkaloid accumulation to the appearance or disappearance of any one metabolite in particular. However, other workers have found that the rate of biomass accumulation was directly related to the rate of formation of cellular serpentine (40) (140). 

Figure 2. Geosmin production and fresh biomass accumulation by Streptomyces tendae cultures on Hickey Tresner and Actinomyces Media. Data are expressed 2 SE of a mean (Adapted from ref. 43).

Kahle, P., Beuch, S., Boelke, B., Leinweber, P, and Schulten, H.-R. (2001). Cropping of Mis-canthus in Central Europe Biomass accumulation and influence on soil organic matter and nutrient cycling. Eur. J. Agron. 15,171-184. 

Next, an experiment was run in which 2.5 g/L of sodium butyrate was added to P2 medium to investigate whether it could be converted to butanol. A control experiment was run containing P2 medium. A separate control experiment was run before each experiment. This is essential because biomass accumulation in the reactor changes with time, thus affecting performance of the reactor (5). The reactor produced 4.77 g/L of total ABE, of which acetone, butanol, and ethanol were 1.51,3.14, and 0.12 g/L, respectively (Table 1). It resulted in a total ABE productivity of 1.53 g/(L-h) and a glucose utilization of 29.4% of that available in the feed of 59.1 g/L. The acid concentration in the effluent was 1.56 g/L. Following this, P2 medium was supplemented with sodium butyrate and the experiment was conducted at the same dilution rate. The reactor produced 1.55 g/L of acetone, 4.04 g/L of butanol, and 0.11 g/L of ethanol, for a total ABE concentration of 5.70 g/L, compared with 4.77 g/L in the control experiment. The productivity was 1.82 g/(L-h), compared with 1.53 g/(L-h) for the control experiment. These experiments suggested that butyrate was used by the culture to produce additional butanol. Note that 0.9 g/L of butanol was produced from 1.65 g/L of butyrate (2.5 g/L in feed, 0.85 g/L in effluent). The yield calculations do not include the amount of butyrate that was utilized by the culture. 

V. ecosystem productivity (increase/ decrease biomass accumulation)... 

Clough, B. (1998) Mangrove forest productivity and biomass accumulation in Hinchbrook Channel, Australia. Mangroves Salt Marshes 77, 171-182. 

Pue, K. J., Blum, U., Gerig, T. M., and Shafer, S. R., 1995. Mechanism by which noninhibitory concentrations of glucose increase inhibitory activity of p-coumaric acid on morning-glory seedling biomass accumulation. J. Chem. Ecol. 21, 833-847... 

Ethylene and carbon dioxide are produced by the plant cells in the culture and their respective headspace concentrations increase in the stoppered flasks. As expected, oxygen consumption by the cells results in reduction of the head-space composition. Specific 02 consumption rate and biomass accumulation curves as a function of time are presented in Fig. 2. The biomass accumulated at a rate of approximately 0.05 gdw 1 1 h the average specific 02 consumption rate calculated as 0.05 mmol gih v h The same data plotted as specific 02 con-... 

Fig. 2. Specific oxygen consumption rate (g 02 gX h-1) and biomass accumulation (gdw per culture flask) of A. annua from type a cultures as a function of time. Consumption ( ) biomass (a)...

In many organisms, the addition of P, to a culture previously deprived of phosphorus results in a rapid accumulation of PolyP to an extent many times exceeding the level which is characteristic of normal growth on a complete medium. This phenomenon is called hypercompensation or phosphate overplus . In E. coli, this effect was not found. The addition of P to a starved culture resulted in a rapid restoration of biomass accumulation. 

Our analysis focuses on three measures of secondary forest development biomass accumulation, nutrient accumulation, and hydrological recovery. We choose biomass accumulation, because it is the best integrative measure of secondary forest development, it is the basis for estimates of carbon sequestration by secondary forests, and it is the most frequently measured secondary forest parameter. An analysis of nutrient accumulation allows us to examine the commonly held assumption that nutrient shortages limit rates of secondary forest recovery (e.g. Gehring et al. 1999, Tucker et al. 1998). Although hydrological recovery in secondary forests is poorly documented in... 

Secondary forests accumulate biomass over time through the growth of woody plants. Biomass accumulation can be measured by monitoring permanent plots in secondary forests over a period of several years, or by using the chronosequence... 

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