## 2 Microbial C\({}_{30}\) Carotenoids and Their Derivatives
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{\(\mathbf{C_{\oplus}}\)**Carctenoid**} & \multirow{2}{*}{\begin{tabular}{c} **Quenching** \\ **Type** \\ \end{tabular} } & \multicolumn{3}{c}{**Antioxidant Activity**} & \multicolumn{1}{c}{**Conjugated**} & \multirow{2}{*}{\begin{tabular}{c} **Group** \\ **Contained** \\ \end{tabular} } & \multicolumn{1}{c}{**H Bond**} & \multirow{2}{*}{\begin{tabular}{c} **Microbial** \\ **Sources [Ref.]** \\ \end{tabular} } \\  & & \multicolumn{1}{c}{**Type**} & \multicolumn{1}{c}{**Carctenoid**} & \multicolumn{1}{c}{**Antioxidant**} & \multicolumn{1}{c}{**Double**} & \multicolumn{1}{c}{**Bond**} & \multicolumn{1}{c}{**Contained**} & \multicolumn{1}{c}{**Done/Acceptor**} & \multicolumn{1}{c}{**Sources [Ref.]**} \\ \hline \multirow{4}{*}{\(4.4^{\prime}\)-Dapo-carstone (4.4^{\prime}\)-Dapo-carstone (4.4^{\prime}\)-Dapo-carstone (4.4^{\prime}\)-Dapo-carstone (4.4^{\prime}\)-Dapo-carstone (4.4^{\prime}\)-Dapo-carstone (4.4^{\prime}\)-Dapo-carstone (4.4^{\prime}\)-Dapo-pythotane/C\({}_{30}\)H\({}_{44}\)} & \multirow{4}{*}{-} & \multirow{4}{*}{-} & \multirow{4}{*}{7} & \multirow{4}{*}{Hydrocarbon} & \multirow{2}{*}{\(0/0\)} & \multirow{2}{*}{\
\begin{tabular}{c} **Susph/docces** \\ _atress_ [24] \\ \end{tabular} } \\  & & & & & & & & \\ \hline \multirow{4}{*}{\(4.4^{\prime}\)-Dapo-pythotune/C\({}_{30}\)H\({}_{46}\)} & \multirow{4}{*}{-} & \multirow{4}{*}{-} & \multirow{4}{*}{-} & \multirow{4}{*}{-} & \multirow{4}{*}{3} & \multirow{4}{*}{Hydrocarbon} & \multirow{2}{*}{\(0/0\)} & \multirow{2}{*}{
\begin{tabular}{c} **Susph/docces** \\ _atress_ [24] \\ \end{tabular} } \\  & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._The orange pigment 4,4\({}^{\prime}\)-diapolycopene (C\({}_{30}\)H\({}_{40}\); also known as 4,4\({}^{\prime}\)-diapol-\(\psi\),\(\psi\)-carotene, _all-trans_-4,4\({}^{\prime}\)-diapolycopene) is an acyclic carotenoid produced in trace amounts by several species of anoxygenic photosynthetic Heliobacteria and by recombinant _B. subtilis_ and _E. coli_[22; 36; 40]. 4,4\({}^{\prime}\)-Diapolycopen-4-al (C\({}_{30}\)H\({}_{38}\)O; also known as _all-trans_-4,4\({}^{\prime}\)-diapolycopen-4-al, 4,4\({}^{\prime}\)-Diapol-\(\psi\),\(\psi\)-carotene-4-al (International Union of Pure and Applied Chemistry, IUPAC), 4,4\({}^{\prime}\)-diapolycopenal and 4,4\({}^{\prime}\)-diapocaroten-4-al) is an apo carotenoid whose parent molecule is 4,4\({}^{\prime}\)-diapolycopene, 4,4\({}^{\prime}\)-Diapolycopen-4-al is found in trace amounts in _S. aureus_ mutants [20; 24; 38; 41]. 4,4\({}^{\prime}\)-Diapolycopenedial (C\({}_{30}\)H\({}_{36}\)O\({}_{2}\); also known as 4,4\({}^{\prime}\)-diapol-\(\psi\),\(\psi\)-carotenedial, 4,4\({}^{\prime}\)-diapolycopen-4,4\({}^{\prime}\)-diapolycopenen aldehyde and _all-trans_-4,4\({}^{\prime}\)-diapolycopene-4,4\({}^{\prime}\)-dial) is a dialdehyde apocarotenoid also formed from 4,4\({}^{\prime}\)-diapolycopene. It has been isolated from _Staphylococcus_ and methylotrophic bacteria [37; 38]. Although a few studies have confirmed the isolation of C\({}_{30}\) carotenoids, the antioxidant potential and microbial yields of these carotenoids can be underestimated owing to the difficulties faced during analysis. The identification of specific microbial-sourced carotenoids is hindered by their interactions with the materials used in standard protocols or by the limitations of separating intermediates and novel compounds that have variable characteristics from the more common carotenoid standards [42]. Low recovery and high carotenoid losses tend to occur due to their instability in the presence of light, heat, acids, alkali, and oxygen, as well as during chromatography. Therefore, all carotenoids necessitate special care in their handling. Additionally, stereochemical modifications influence their purification and analysis, as the _cis/trans_ configurations affect their biochemistry and stereoisomerism affects their solubility and biofunctionality.