Process development and scale up for microbial PHA production

Although many PHA have been found, only three of them were produced on a large scale for commercial exploitation, these are PHB, PHBV and PHBHHx. Small-scale production of mcl PHA was also conducted. There is still a lot to improve for the production of these unique polyesters. 

Extensive work was conducted for microbial production of PHB and PHBV. Accumulated experience has led to the industrial production of PHB by Chemie Linz AG/Austria in the 1980s, using the bacterial stiaia Alcaligenes latus. However, the poor mechanical properties and weak processibility limited development of PHB as an environmentally friendly packaging material. PHBV was subsequently developed by Zeneca/UK (then ICI or Imperial Chemical Industries Co. Ltd), using Wautersia eutropha as a production strain. PHBV had improved properties over PHB (Table 2.1) and ICI developed PHBV with the Trade name of BIOPOL. 

Bacillus spp. were among the very first to be reported as PHB producers. However, we were surprised to learn that no PHB production research in terms 

PHB produced by the strain is now the subject of study by the Institute of Polymer Sciences and Engineering at Tsinghua University. Major efforts have been focused on improving the mechanical strength and the exploitation of tissue engineering applications for this polyester. 

The strain is able to grow on glucose and produce the copolymer PHBV to a density as high as 70-80 g/1 after over 70 h of growth. Shampoo bottles were produced from PHBV (trademarked as BIOPOL) and were available in supermarkets in Europe. However, due to economic reasons, the Biopol produets did not sueeeed and the PHBV patents were sold to Monsanto and further to MetaboUx. 

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