Recovery of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from Ralstonia eutropha cultures with non-halogenated solvents

Reduced downstream costs, together with high purity recovery of polyhydroxyalkanoate (PHA), will accelerate the commercialization of high quality PHA-based products. In this work, a process was designed for effective recovery of the copolymer poly(hydroxybutyrate-co-hydroxyhexanoate) (P(HB-co-HHx)) containing high levels of HHx (>15 mol%) from Ralstonia eutropha biomass using non-halogenated solvents. Several non-halogenated solvents (methyl isobutyl ketone, methyl ethyl ketone, and butyl acetate and ethyl acetate) were found to effectively dissolve the polymer. Isoamyl alcohol was found to be not suitable for extraction of polymer. All PHA extractions were performed from both dry and wet cells at volumes ranging from 2 mL to 3 L using a PHA to solvent ratio of 2% (w/v). Ethyl acetate showed both high recovery levels and high product purities (up to 99%) when using dry cells as starting material. Recovery from wet cells, however, eliminates a biomass drying step during the downstream process, potentially saving time and cost. When wet cells were used, methyl isobutyl ketone (MIBK) was shown to be the most favorable solvent for PHA recovery. Purities of up to 99% and total recovery yields of up to 84% from wet cells were reached. During polymer recovery with either MIBK or butyl acetate, fractionation of the extracted PHA occurred, based on the HHx content of the polymer. PHA with higher HHx content (17–30 mol%) remained completely in solution, while polymer with a lower HHx content (11–16 mol%) formed a gel-like phase. All PHA in solution could be precipitated by addition of threefold volumes of n-hexane or n-heptane to unfiltered PHA solutions. Effective recycling of the solvents in this system is predicted due to the large differences in the boiling points between solvent and precipitant. Our findings show that two non-halogenated solvents are good candidates to replace halogenated solvents like chloroform for recovery of high quality PHA. Biotechnol. Bioeng. 2013; 110: 461–470. © 2012 Wiley Periodicals, Inc.Malaysia-MIT Biotechnology Partnership Programm

The effects of varying levels of Nigella sativa seed meal supplementation on nutrient digestibility and rumen fermentation characteristics in goats

The supplementations of various herbal feed additives with many nutritional properties have been widely investigated. The present study aims to investigate the effects of Nigella sativa seed meal (NSM) supplementation on nutrient digestibility and rumen fermentation characteristics of goats. In doing so, five mixed breed adult male goats were fed ad libitum with guinea grass hay (as basal diet), supplemented with NSM (DMI based on 1.5% of body weight) at 0% (NSM0), 0.8% (NSM8), 1.6% (NSM16) and 2.4% (NSM24). A mixture of Feral with Boer and Katjang breed of goats were used in this study. This study was carried out as a cross-over design of a 3-week cycle (2-weeks of adaptation and 1-week of experimental) and resumed after 1-week of washout period. It was revealed that there were no significant differences in nutrient digestibility of DM, OM, CF, DE, ADF, ADL and NDF, rumen pH, total VFA, individual VFA proportions and acetate: propionate ratio between control and NSM supplemented groups. Therefore, the results has proven that the addition of 0.8%, 1.6% and 2.4% NSM supplementation did not cause any adverse impact on feed digestibility and rumen fermentation characteristics of the goats. However, a larger number of replicates on the tolerance levels of NSM concentration in the dietary treatment of goats should be studied further

Dietary supplementation of black cumin seed meal on rumen fermentation in goats

Improving production is important in ruminant industry and to solve this problem, much effort has been carried out to manipulate the rumen ecosystem as it plays an important role in ruminant nutrition. The use of herbal by-products has been considered in order to maximize the usage of herbs and to reduce feed cost. Black cumin seed meal is the by-product of Nigella sativa seed that has been pressed to produce oil and is also believed to contain nutrients that are not fully removed from the whole seed. As such, the present study was to evaluate the effect of black cumin seed meal supplementation on nutrient digestibility, rumen fermentation characteristics, rumen fatty acid profiles and rumen total protozoal counts of goats fed with black cumin seed meal-based feed. In the first part of the study, proximate analysis, fatty acid profiling and determination of saponin and flavonoid of the black cumin seed meal were conducted. In this study, total of five rumen fistulated mixed breed male goats between 18 kg to 20 kg of body weight were used. All goats were fed on 1.5% dry matter (DM) of body weight with formulated concentrate diets supplemented with four levels of black cumin seed meal and 1.5% DM of body weight guinea grass hay as basal diet. The four levels of black cumin seed meal were fixed at 0% (BC0), 0.8% (BC8), 1.6% (BC16) and 2.4% (BC24). The goats were subjected to a three week cycle consisting of two weeks adaptation and one week of experimentation. After one week of washout period, the cycle was resumed. The feeding regime consisted diets supplemented with different levels of black cumin seed meal with guinea grass hay, ad libitum feeding. Results had shown that the black cumin seed meal had 31.2% crude protein,19.2% crude fat, 56% linoleic acid and 0.41% linolenic acid. The saponin content in the black cumin seed meal was about 0.139 mg /100 g while flavonoid content about 3.0 mg / 100 g. The pH of rumen in goats fed with dietary treatments ranged from 6.5 to 7.0 throughout the study. The supplementation of black cumin seed meal had no effect (P>0.05) on all the fatty acid proportions. There were also no significant differences (P>0.05) between dietary treatments on the total VFA concentrations, molar proportions of individual VFA, or ratio of acetate to propionate. The total mean protozoa numbers were also constant throughout the study. In conclusion, the supplementation of black cumin seed meal at 0.8%, 1.6% and 2.4% in the diets did not affect nutrient digestibility, rumen fermentation characteristics, rumen fatty acid profiles and total protozoa counts of the goats

Synthesis and evaluation of highly dispersed SBA-15 supported Ni–Fe bimetallic catalysts for steam reforming of biomass derived tar reaction

Highly dispersed Ni–Fe bimetallic catalysts supported on mesoporous SBA-15 were synthesized via an incipient wetness impregnation method by impregnation of a small amount of oleic acid mixed with a metal precursor on the SBA-15 support.</p

High performance oxygen permeable membranes with Nb-doped BaBi0.05Co0.95O3-δ perovskite oxides

10.1016/j.memsci.2012.11.072Journal of Membrane Science431180-186JMES

A new asymmetric SrCo0.8Fe0.1Ga0.1O3-δ perovskite hollow fiber membrane for stable oxygen permeability under reducing condition

10.1016/j.memsci.2012.11.005Journal of Membrane Science42878-85JMES