Several processes for the production and recovery of poly(3-hydroxybutyrate) (PHB) by Alcaligenes eutrophus, Alcaligenes latus, Methylobacterium organophilum, and recombinant Escherichia coli were designed based on the previously reported data and analyzed by computer-aided bioprocess design. PHB productivity, content, and yield signi®cantly affected the ®nal price of PHB. For the annual production of 2,850 tonnes of puri®ed PHB, the process employing A. eutrophus with the recovery method of surfactant-hypochlorite digestion resulted in lowest price of PHB, $ 5.58/kg. As the production scale increased to one million tonnes per year, the price of PHB dropped to $ 4.75/kg. The cost of carbon substrate signi®cantly affected the overall economics in large production scale. Therefore, the production cost can be considerably lowered when agricultural wastes, such as whey and molasses, are used.

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A simple method for the recovery of microbial poly(3‐hydroxybutyrate) [P(3HB)] from recombinant Escherichia coli harboring the Ralstonia eutropha PHA biosynthesis genes was developed. Various acids (HCl, H2SO4), alkalies (NaOH, KOH, and NH4OH), and surfactants (dioctylsulfosuccinate sodium salt [AOT], hexadecyltrimethylammonium bromide [CTAB], sodium dodecylsulfate [SDS], polyoxyethylene‐p‐tert‐octylphenol [Triton X‐100], and polyoxyethylene(20)sorbitan monolaurate [Tween 20]) were examined for their ability to digest non‐P(3HB) cellular materials (NPCM). Even though SDS was an efficient chemical for P(3HB) recovery from recombinant E. coli, it is expensive and has waste disposal problem. NaOH and KOH were also efficient and economical for the recovery of P(3HB), and therefore, were used to optimize digestion condition. When 50 g DCW/L of recombinant E. coli cells having the P(3HB) content of 77% was treated with 0.2 N NaOH at 30°C for 1 h, P(3HB) was recovered with purity of 98.5%. Using this simple recovery method, the effect of recovery method on the final production cost of P(3HB) was examined. Processes for the production of P(3HB) by recombinant E. coli from glucose with two different recovery methods, surfactant‐hypochlorite digestion and simple digestion with NaOH, were designed and analyzed. By employing the fermentation process that resulted in P(3HB) concentration, P(3HB) content and P(3HB) productivity of 157 g/L, 77%, and 3.2 P(3HB) g/L‐h, respectively, coupled with the recovery method of NaOH digestion, the production cost of P(3HB) was US$ 3.66/kg P(3HB), which was 25% less than that obtained by employing the surfactant‐hypochlorite digestion method. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 62: 546–553, 1999.

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The newly screened Aeromonas hydrophila produces copolymer consisting of 3‐hydroxybutyrate (3HB) and 3‐hydroxyhexanoate (3HHx). The characteristics of cell growth and polymer accumulation were examined using various carbon sources. P(3HB‐co‐3HHx) was produced from lauric acid and oleic acid only. P(3HB‐co‐3HHx) content can be increased by limitation of phosphorus. A maximal P(3HB‐co‐3HHx) content of 28.8 wt% could be obtained in flask culture. By applying the optimally designed nutrient feeding strategy, cell dry weight, P(3HB‐co‐3HHx) content, and 3HHx fraction obtained over the course of 43 h were 95.7 g/L, 45.2 wt%, and 17 mol%, respectively, resulting in a productivity of 1.01 g polyhydroxyalkanoate (PHA)/L · h. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 67: 240–244, 2000.

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Our results indicate that SLE patients present with different clinical and serological manifestations according to age at disease onset. JSLE patients have more severe disease activity and more frequent renal involvement and LSLE patients have milder disease activity, more commonly accompanied by Sjögren's syndrome, at disease onset.

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