ABSTRACT
En este trabajo se determinó el rendimiento de polihidroxialcanoatos (PHA) producido por microorganismos aislados de suelo y aguas de las salinas de Morrope, Lambayeque, Perú. La población de microorganismos se enriqueció con caldo HM1, con glucosa (15 gL-1) como fuente de carbono, modificado con 15, 20 y 25 g/100 mL de NaCl, se incubó a 30 °C en aerobiosis hasta observar turbidez o película por el crecimiento se aisló en agar HM1 obteniendo cultivos de microorganismos halófilos. En caldo HM2 con glucosa (30 gL-1), con su respectiva concentración de NaCl se investigó la producción de gránulos de PHA y se determinó el tiempo requerido para observar el mayor número de células con gránulos de PHA. Los 20 cultivos con mayor número de células con gránulos se llevaron a fermentación a caldo HM2, cuantificándose la biomasa y PHA. La naturaleza del polímero y cálculo del rendimiento se realizó con cinco aislados microbianos correspondientes a la mayor concentración de NaCl, el mayor número de celular con gránulos en el menor tiempo. Se obtuvieron 234 aislados de microorganismos y en el 38.74% se observó gránulos de PHA mediante la tinción de Sudan Negro B, seleccionándose 20 cultivos de microorganismos con 40 a 85 células con gránulos de PHA. La biomasa osciló entre 0.005 a las 72 horas y 3.211 gL-1 a las 240 horas. El rendimiento p/x fue de 0.270 a 0.725 gg-1, destacando con más de 60% los microorganismos AE222 (60.73%), AE2019 (63.10%) y AE228 (72.52%). Estos microorganismos son considerados promisorios para la producción de PHA.
In this work, we determine the polyhydroxyalkanoates (PHA) yield of microorganisms of soil and water from salty lagoons of Morrope, Lambayeque, Peru. Microorganisms were enriched in modified HM1 broth with 15, 20 and 25 g/100 mL of NaCl, incubated at 30 °C in aerobiosis. After observed turbidity or film, aliquots were taken and seeded on HM1 agar obtaining 234 bacterial isolates that by lipophilic Sudan Negro B staining were observed the presence of 93 bacterial isolates with PHA granules, which were cultured in HM² broth with their respective concentrations of NaCl for 144 hours, quantifying a range of 4-85 cells with granules in five microscopic fields observed, selecting 20 bacterial isolates with the presence of 40-85 cells with granules, then they were taken to fermentation where the optimal incubation time was determined, where the cells are clearly differentiated with PHA granules. To determine the nature of the polymer produced, five bacterial isolates corresponding to the culture with the highest concentration of NaCl and the highest number of cells with PHA granules with the shortest growth time, but not necessarily the highest biomass, were selected, these reached 0.500; 0.300; 0.167; 0.183 and 0.417 gL-1 of PHA, with 1.850; 0.522; 0.275; 0.290 and 0.575 gL-1 of biomass and 0.270; 0.575; 0.607; 0.631 and 0.725 gg-1 yield Y (p/x). The highest yield was 72.52% of cellular mass in PHA being considered a promising and profitable performance for the extraction of the polymer.
ABSTRACT
Poly (3-hydroxypropionate) (P3HP), a new member of thermoplastic of family polyhydroxyalkanoates (PHAs), has excellent characteristics of biodegradability and biocompatibility. By now no reports can be found about wild-type bacteria that naturally synthesize P3HP, so the main way to produce P3HP is chemical and biological methods. Chemical method by adding high cost 3-HP monomers or their structural analogs as precursors, has the drawbacks of toxicity, low effectiveness and high cost. Biological method using engineered strain may utilize inexpensive and renewable carbon source to produce P3HP and has gradually become more and more popular. We systematically review here the biosynthesis of P3HP research progress. The advantages and disadvantages of biosynthesis pathways of glycerol pathway, malonyl-CoA pathway and β-alanine pathway were analyzed.
ABSTRACT
Large quantity of activated sludge is generated from wastewater treatment but without yet an appropriate deposition. High temperature can lyse the activate sludge so that nitrogen and phosphorus containing nutrients are released. Halomonas CJN was found to grow on the heat lysed activated sludge and glucose for production of bioplastic poly-3-hydroxybutyrate (PHB) in the absence of yeast extract, nitrogen and phosphorus sources as well as trace elements. This reduces the PHB production cost significantly. Furthermore, acetic acid formed from anaerobic fermentation of heat lysed activated sludge can be used to replace glucose for cell growth but not much for PHB production. After construction of an additional PHB synthesis pathway in Halomonas CJN, we can produce PHB entirely from heat lysed activated sludge, reducing production cost of PHB roughly from ¥ 30 000 Yuan/ton to ¥ 20 000 Yuan/ton, thus turning waste activated sludge to valuable raw material resource.