Biomass measurement

Biomass is a fundamental parameter in the characterization of microbial growth. Direct measurement of biomass is not possible in SSF because microbial biomass cannot be separated from the substrate. But absolute amount of biomass is important for the calculation of growth rates and yields. Since direct measurement of biomass is difficult, a global stoichiometric equation of microbial growth can be considered. 

Carbon source + Water + Oxygen + Phosphorus + Nitrogen Biomass + CO2 + Metabolites + Heat 

Measuring any one of the above component allows the determination of the evolution of others if all the coefficients are maintained constant. 

Biomass growth can be measured by considering the carbon dioxide release and oxygen uptake. The metabolism of these compounds is completely growth-associated, which means that the biomass produced per unit of gas metabolized must be constant. Carbon compounds present in the substrate are used by the organism to build up biomass. 

Biomass growth can also be determined by measuring the cell or mycelia component that is not present in solid substrate. Protein content of the biomass can be measured by determining the nitrogen content by the Kjeldahl method. Accurate measurement of biomass can be obtained using an amino acid analyzer. This method of biomass measurement is reliable if the solid substrate has no protein content. 

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Laboratory Microfiltration membranes have countless laboratory uses, such as recovering biomass, measuring particulates in water, clarifying and sterilizing protein solutions, and so on. There are countless examples for both general chemistry and biology, especially for analytical proc ures. Most of these apphcations are run in dead-end flow, with the membrane replacing a more conventional medium such as filter paper. 

Most of the studies05,20 271 show that a correlation between culture fluorescence and biomass concentration can be obtained mainly in the exponential growth phase. In addition, in order to obtain reproducible correlations, all of the fermentation conditions such as initial substrate concentration, pH, dissolved oxygen level, temperature, and agitation rate have to be the same. However, once the culture is past exponential growth, biomass measurement by following culture fluorescence is no longer accurate. 

Yokelson, R. J., R. Susott, D. E. Ward, J. Reardon, and D. W. T. Griffith, Emissions from Smoldering Combustion of Biomass Measured by Open-Path Fourier Transform Infrared Spectroscopy, . /. Geophys. Res., 102, 18865-18877 (1997). 

Understanding the factors controlling organic matter turnover is complicated by possible differences in population distributions of organisms responsible for enzyme production and product uptake. Although relationships between enzyme Vmax and bacterial productivity have been reported (Sinsabaugh et al., 1997), correlations between total bacterial numbers or bacterial production and enzyme activities are frequently found to be variable or weak (e.g., Mayer, 1989 Boetius et al., 1996, 2000). Vrba et al. (1992) observed that MUF-a-glucosidase activity correlated with bacterial biomass measured in a freshwater reservoir over the course of three seasons,... 

Estimates of biomass from ninhydrin-reactive N measurements (Amato and Ladd 1988) have many advantages. The method is extremely quick (involving a simple colorimetric determination, thus avoiding a tedious digestion step), reliable, and accurate. Biomass measurements of ninhydrin-reactive N (Bnin) are also closely correlated with total biomass N (BN)... 

Ocio, J. A. and Brookes, P. C. (1990b). Soil microbial biomass measurements in sieved and unsieved soil. Soil Biol. Biochem. 22,999-1000. 

Measured NPP is more of an index of net primary production than a true value. Most field measurements of NPP document only the new plant biomass produced and therefore probably underestimate the true NPP by at least 30% (Table 1). There are many sources of error to this estimate. Some biomass above and below ground dies or is removed by herbivores before it can be measured, so even the new biomass measured in field studies is an underestimate of biomass production. Root exudates are rapidly taken up and respired by microbes adjacent to roots and are generally measured in field studies as a portion of... 

II. Weight of soil (oven dry weight equivalent) taken for microbial biomass measurement (Ws). 

Martz, R.F., Sebacher, D.l. and White, D.C. (1983) Biomass measurement of methane forming bacteria in environmental samples. Journal of Microbiological Methods 1, 53-61. 

There have been numerous estimates made on the total biomass and biomass potential of our forests 3,1Q). The inventory procedure used is based on estimates and averages, and is fully described by Wahlgren and Ellis (U). Forest surveys based on biomass measurement techniques are needed to accurately determine the quantities and location of our wood resource. Many studies on measuring the weight of individual trees, and to a lesser extent forest stands, have been made. This work has been summarized by Keays (12). and Hitchcock and McDonnell (12)- As work in forest biomass measurement is refined, regional weight tables can be developed and accurate biomass inventories compiled. 

Growth of biomass is typically of crucial importance in SSF processes, even if the biomass itself is not the final product. The processes of nutrient consumption, oxygen consumption, carbon dioxide evolution, waste heat release, and product formation are intimately related to the growth process and therefore it is usually essential to characterize the growth curve. Unfortunately, on-line biomass measurement is still impossible in SSF, despite efforts to develop on-line sensors based on Fourier transform infrared spectroscopy [176]. 

A turbidostat mode of operation relies on the use of a sensor to measure the biomass concentration in the photobioreactor. Such a sensor can be based on the online measurement of culture turbidity, for example, but any other biomass sensor can be used as well. Based on such a continuous biomass measurement the flow rate through the system then is automatically adjusted such that the biomass concentration is maintained at a preselected value (Fig. 29). 

Kiviharju, K., Salonen, K., MoUanen, U., Eerikainen, T. (2008). Biomass measurement online the performance of in situ measurements and software sensors. Journal of Industrial Microbiology and Biotechnology, 35, 657-665. 

The fundamental aspects as well as design and operations of SSF have been well elaborated by Pandey et al. [3, 4, 11]. These include the selection of the microorganism, specific growth rate, biomass measurement, and so on, which also have been described by several other authors [12-15]. 

In SSF, it is not as easy as in SmF to measure the biomass. In this chapter, indirect ways of biomass measurement for SSF are discussed. 

Steudler, S., Bohmer, U., Weber, J., and Bley, T. (2015) Biomass measurement by flow cytometry during solid-state fermentation of basidiomycetes. Cytometry A, 87, 176-188. 

P, mainly in the form of RNA and DNA, polyphosphates and phospholipids, with minor amounts of other P-containing cell biochemicals like adenosine phosphates. Measurement of the P content of the microbial biomass is an essential prerequisite for assessing its role in the P cycle, and its effect on plant nutrition. Until very recently, estimates of microbial P have had to be made from microbial biomass measurements, and literature values for the P contents of laboratory cultured microorganisms which can vary widely depending on growth conditions. ... 

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