Thermodynamic properties of microorganisms: determination and analysis of enthalpy, entropy, and Gibbs free energy of biomass, cells and colonies of 32 microorganism species

Abstract

Thermodynamic analysis is an important part of chemical engineering. However, its application in biotechnology has been hampered by lack of data on thermodynamic properties of microorganism biomass. In this paper, a review was made of methods for estimation of thermodynamic properties of biomass, including standard enthalpy of combustion h C ⁰ , enthalpy of formation h f ⁰ , entropy s⁰ , and Gibbs free energy of formation g f ⁰ . These parameters were calculated on molar and mass specific basis for 32 microorganism species, including 14 bacteria, 7 yeast and 11 algae species. It was found that h f ⁰ , s⁰ , g f ⁰ are, respectively, similar for all the analyzed species, due to the fact that all living organisms have a common ancestor and thus a similar chemical composition. Furthermore, all the analyzed microorganisms have negative h f ⁰ , originating from partial oxidation of all other elements by oxygen and nitrogen. A brief review was given of microorganism endogenous and growth metabolic rates. Finally, based on the determined thermodynamic properties, entropy of individual E. coli and Pseudomonas cells were determined and entropy of a Pseudomonas colony during its lifespan was calculated and analyzed. Three periods can be distinguished in the existence of a microorganism colony: (a) accumulation period when cell number, mass and entropy increase, (b) steady state period when they are approximately constant, and (c) decumulation period when they decrease.

Thermodynamic insight into viral infections 2: empirical formulas, molecular compositions and thermodynamic properties of SARS, MERS and SARS-CoV-2 (COVID-19) viruses

“…Thus, there is a difference in empirical formulas of both the nucleocapsids and entire viruses between SARS, MERS and SARS-CoV-2. For comparison, the empirical formulas of other classes of organisms are: bacteria CH 1.7 O 0.4 N 0.2 , fungi CH 1.7 O 0.5 N 0.1 , algae CH 1.7 O 0.5 N 0.1 ( Popovic, 2019 ) and human soft tissue average CH 1.7296 O 0.2591 N 0.1112 P 0.0134 S 0.0030 Na 0.0027 K 0.0031 Ca 0.0173 Cl 0.0018 ( Popovic and Minceva, 2020a ). The empirical formulas are similar to those of other classes of organisms.…”

“…The Roels method was used to see whether changing the method of estimating thermodynamic properties has influence on the conclusions (Section 3.3.2 ). The uncertainties in determining thermodynamic properties are 5.36% for Patel-Erickson ( Popovic, 2019 ) and 19.7% for Battley equation ( Battley, 1999 ; Popovic, 2019 ).…”

“…Thermodynamic properties (Δ f H⁰ ( bio ), S⁰ m ( bio ) and Δ f G⁰ ( bio )) were determined from elemental composition using empirical relations and thus have some uncertainty. Δ C H⁰ was found using the Patel-Erickson equation, the uncertainty of which is 5.36% ( Popovic, 2019 ). The determined Δ C H⁰ values were then subtracted from standard enthalpies of formation of oxides ( Eq.…”

“…Δ f H⁰ ( bio ) and Δ f S⁰ ( bio ) are used to find Δ f G⁰ ( bio ). Therefore, the uncertainty in the standard Gibbs energy of formation of live matter, δ (Δ f G⁰ ( bio )), is ( Popovic, 2019 ) …”

A Review of Methods to Determine Viability, Vitality, and Metabolic Rates in Microbiology

“…Indeed, using the enthalpy of reaction provides an additional equation that can further help solve the equation system. The enthalpy of reaction ( H rxn ) measured by the calorimeter can also be calculated using enthalpy of formation ( H f ) or of combustion ( H c ); using enthalpy of combustion simplifies the equation even more (see details in Maskow and Harms, 2006;Barros et al, 2010;Maskow et al, 2010 Maskow et al, 2010) The enthalpies of formation and combustion of organic matter, and especially organic matter from microbial biomass, can be found in several review papers (Cordier et al, 1987;von Stockar et al, 1993;Popovic, 2019), thus making this approach easy to implement with relatively high accuracy.…”