# Enzymatic Synthesis of Biobased Polyesters and Polyamides
## 3 Polyamides  
Polyamides are polymers in which the monomeric units are linked together by amide bonds. Examples of polyamides include naturally occurring polyamides like proteins, and synthetic polyamides such as polycaprolactone (nylon 6 or PA 6), poly(hexamethylene adipamide) (nylon 6,6 or PA 6,6), poly(hexamethylene terephthalamide) (PA 6,T), and poly(\(p\)-phenylene terephthalamide) (PPTA, Kevlar(r), DuPont, Wilmington, DE, USA). Similar to polyesters, polyamides can be classified to three types: aliphatic, semi-aromatic and aromatic polyamides, depending on the chemical composition of the main chain (Scheme 2). Aliphatic polyamides, commercially known as nylons or nylon fibers, are highly valued semi-crystalline thermoplastics that are widely used as synthetic fibers, construction materials, food packing materials, engineering resins, and so on [69]. Currently, a variety of aliphatic polyamides are commercially manufactured, including nylon 6 (PA 6), nylon 10 (PA 10), nylon 11 (PA11) and nylon 12 (PA 12), and nylon 4,6 (PA 4,6), nylon 6,6 (PA 6,6), nylon 6,10 (PA 6,10) and nylon 6,12 (PA 6,12). Among them, nylon 6 is the largest produced aliphatic polyamide by far, with a global production of 4.2 million tons in 2010; and nylon 6,6 ranked the second largest aliphatic polyamide \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Biobased Polyester** & **Biosourcing (\%) \({}^{\star}\)** & **Manufacturer** & **Tademark** \\ \hline \multirow{8}{*}{PLA} & \multirow{8}{*}{up to 100} & NatureWorks (Mimenteau, MN, USA) & Inge\({}^{10\%}\), NatureWorks(r) \\  & & Sprube (Etene-Leur, The Netherlands) & BioForm(r) \\  & & Zhejiang Hsiam Biomaterials Biological Engineering & & REVOO 100 and 200 series \\  & & \multirow{4}{*}{Nantong Jiotag Jiotogical Engineering (Rugao, Jiangsu, China)} & \multirow{4}{*}{-} \\  & & Teljin (Chiyoda, Tokyo, Japan, Japan) & & BROFRONT(r) \\  & & Mitsui Chemnica, Tokyo, Japan) & LALCA(r) \\  & & Future (Collen, Belgium) & Futerer(r) \\  & & Corbion Purace (Amsterdam, The Netherlands) & LX175, L175, L133, L105, D070 \\ \hline \multirow{8}{*}{PHAs} & \multirow{8}{*}{100} & Metabolic (Cambridge, MA, USA) and ADM (Decatur, IL, USA) & Mirae(tm) \\  & & \multirow{4}{*}{MIG (Bair, China)} & MIG (Bair, China) \\  & & Bio-on (San Ginggio di Piano, Belogas, Italy) & MNEWF-PHA(tm) \\  & & Tamjin Green Biosciences (Tangni, China) & Greenhof \\  & & Kaneda (Tokyo, Japan) & Kaneda PHBH \\  & & Thanan Biological Materials (Ninging, Zhejiang, China) & IEMMAT(tm) \\  & & PIB Industrial S/A (Serran, Brazil) & BROCYCL(tm) \\ \hline \multirow{2}{*}{PBS} & \multirow{2}{*}{50} & FIT MCC Bicochem ( Chhatsouk, Bangokok, Thailand) & BioPRS(tm) \\  & & Showa Denko K.K. (Tokyo, Japan) & Biomello(tm) \\  & & Mitsubishi Chemical(Chiyoda-ku, Tokyo, Japan) & CS Pls(tm) \\ \hline PEF & 100 & Avantium (Gelcer, The Netherlands) & - \\ \hline \multirow{2}{*}{PET} & \multirow{2}{*}{up to 30} & Coca Cida (Atlanta, GA, USA) & PlantRottle(tm) \\  & & Toyota Tususho Corporation (Nagoya, Aichi Prefecture, Japan) & GLOB(tm) \\ \hline \multirow{2}{*}{PTT} & \multirow{2}{*}{37} & DuPont (Wilmington, DE, USA) & Sorona(tm) \\  & & up to 35 & DuPont (Wilmington, DE, USA) & Biomass(tm) \\ \hline \multirow{2}{*}{PBAT} & \multirow{2}{*}{30–70} & Novamont (Novara, Italy) & Origo-B(tm) \\  & & BASF (Ludwighafen, Germany) & Ecofoflex(tm) PS \\ \hline \multicolumn{2}{l}{C\(\alpha\)-polyester} & \multirow{2}{*}{9-30} & SK Chemicals (Seongam-si, Gyenopsis-do, Korea) & ECOZEN(tm) \\ \hline \multicolumn{2}{l}{C\(\alpha\)-polyester} & \multirow{2}{*}{-} & DuPont (Wilmington, DE, USA) & Biomass(tm) \\ \hline \hline \end{tabular}  
* Biosourcing (%): the percentage of carbon originating from biomass sources among the total organic carbon.  
\end{table} 
Table 1: A selected list of commercially available biobased polyesters and their manufacturers. in the market, with a global production of 2.1 million tons.