# Microbial Biosynthesis of Lactones: Gaps and Opportunities towards Sustainable Production
## 4 Microbial Production
### De Novo Biosynthesis
pae_} & \(\varsigma\)-6-\(\gamma\)-dodecenolactone & & Up to 23 mg/L & & \\  & \(\gamma\)-decalactone & & Up to 1.0 mg/L & & \\  & \(\gamma\)-monalactone & & Up to 0.6 mg/L & & \\  & \(\gamma\)-octadecanc & & Up to 0.6 mg/L & & \\  & \(\gamma\)-octadecanc & & Up to 0.6 mg/L & & \\  & \(\gamma\)-dodecalactone & & Up to 0.1 mg/L & & \\  & \(\gamma\)-valerolactone & & Up to 0.1 mg/L & & \\  & \(\gamma\)-valerolactone & & Up to 0.1 mg/L & & \\ \cline{2-6}  & \(\varsigma\)-6-\(\gamma\)-dodecenolactone & Malt extract & 2.0 mg/L & - & [34] \\ \cline{2-6} _F. pae_ & \(\gamma\)-dodecalactone & & & & \\  & \(\gamma\)-decalactone & & & & \\  & \(\delta\)-decalactone & & & & \\  & \(\gamma\)-caprolactone & & & & \\  & \(\gamma\)-octalactone & & & & \\  & \(\gamma\)-uncalactone & & & & \\  & \(\gamma\)-valerolactone & & & & \\ \hline \multirow{9}{*}{_S. salmonicolor_} & \multirow{9}{*}{\(\gamma\)-decalactone} & Glucose & Up to 11 mg/L & 12 days & [40] \\ \cline{2-6}  & & \( \begin{array}{c}\text{Fructose}\\ \text{Sucrose}\end{array} \) & \( \begin{array}{c}\text{Up to 1.9 mg/L}\\ \text{1.5 mg/L}\end{array} \) & 8 days & [38] \\ \cline{2-6}  & & \( \begin{array}{c}\text{Mannitol;}\\ \text{sucrose;}\text{fructose}\end{array} \) & \( \begin{array}{c}\text{Up to 4.5 mg/L}\\ \text{Up to 2.7 mg/L}\end{array} \) & & & [38] \\ \cline{2-6}  & & \( \begin{array}{c}\text{Mannitol;}\\ \text{type to 1.9 mg/L}\end{array} \) & \( \begin{array}{c}\text{Up to 2.7 mg/L}\\ \text{1.8 days}\end{array} \) & 8 days & [38] \\ \cline{2-6} _S. salmonicolor_ & & Glucose & Up to 3.0 mg/L & 6–9 days & [40] \\ \cline{2-6}  & \( \begin{array}{c}\text{$\gamma$-dodecalactone}\\ \text{$\gamma$-onalactone}\end{array} \) & Glucose & Up to 0.4 mg/L & & \\  & \( \begin{array}{c}\text{$\gamma$-nonalactone}\\ \text{$\gamma$-octalactone}\end{array} \) & Glucose & Up to 0.3 mg/L & 6–9 days & [40] \\ \cline{2-6}  & \( \begin{array}{c}\text{$\gamma$-octalactone}\end{array} \) & Glucose & Up to 25 ug/L & & \\ \cline{2-6}  & \( \begin{array}{c}\text{$\delta$-jasmin lactone}\\ \text{$\delta$-decalactone}\end{array} \) & \( \begin{array}{c}\text{Fructose}\\ \text{$\text{Fructose}}\end{array} \) & - & - & [39] \\ \cline{2-6}  & \( \begin{array}{c}\text{$\gamma$-dodecalactone}\end{array} \) & \( \begin{array}{c}\text{Potato dextrose}\end{array} \) & 170 mg/L & 3–4 days & [35] \\ \cline{2-6}  & \( \begin{array}{c}\text{$\delta$-pentyl-$\alpha$-pyrone}\end{array} \) & \( \begin{array}{c}\text{Potato dextrose}\end{array} \) & 170 mg/L & 3–4 days & [35] \\ \cline{2-6}  & \( \begin{array}{c}\text{$\delta$-pentyl-$\alpha$-pyrone}\end{array} \) & \( \begin{array}{c}\text{Up to 3.6 mg/g}\\ \text{$\text{Up to 0.3 mg/g}$-g}\end{array} \) & 5 days & & \\ T. _viride_ & \( \begin{array}{c}\text{$\gamma$-undecalactone}\end{array} \) & \( \begin{array}{c}\text{Spagarcane bagasse}\end{array} \) & \( \begin{array}{c}\text{Up to 0.1 mg/g}\end{array} \) & 9 days & [12] \\ \cline{2-6}  & \( \begin{array}{c}\text{$\delta$-octalactone}\end{array} \) & \( \begin{array}{c}\text{Up to 52 ug/g}\end{array} \) & 5 days & & \\ \cline{2-6}  & \( \begin{array}{c}\text{$\delta$-dodecalactone}\end{array} \) & \( \begin{array}{c}\text{Up to 59 mg/g}\end{array} \) & 9 days & & \\ \cline{2-6}  & \( \begin{array}{c}\text{$\gamma$-dodecalactone}\end{array} \) & \(\begin{array}{c}\text{Up to 36 mg/g}\end{[PERSON] and [PERSON] (1972) were the first to demonstrate that the characteristic coconut-like aroma in _T. viride_ was due to the presence of 6-pentyl-\(\alpha\)-pyrone, an unsaturated \(\delta\)-lactone [35]. This lactone was produced from a medium based on sugars, indicating the ability of this fungus to de novo biosynthesize this compound. Moreover, its production was associated with spores rather than the mature mycelia, suggesting a production pattern linked with the growth phase [35].