Anaerobic fermentation of glycerol: a path to economic viability for the biofuels industry

Although biofuels such as biodiesel and bioethanol represent a secure, renewable and environmentally safe alternative to fossil fuels, their economic viability is a major concern. The implementation of biorefineries that co-produce higher value products along with biofuels has been proposed as a solution to this problem. The biorefinery model would be especially advantageous if the conversion of byproducts or waste streams generated during biofuel production were considered. Glycerol-rich streams generated in large amounts by the biofuels industry, especially during the production of biodiesel, present an excellent opportunity to establish biorefineries. Once considered a valuable 'co-product', crude glycerol is rapidly becoming a 'waste product' with a disposal cost attributed to it. Given the highly reduced nature of carbon in glycerol and the cost advantage of anaerobic processes, fermentative metabolism of glycerol is of special interest. This review covers the anaerobic fermentation of glycerol in microbes and the harnessing of this metabolic process to convert abundant and low-priced glycerol streams into higher value products, thus creating a path to viability for the biofuels industry. Special attention is given to products whose synthesis from glycerol would be advantageous when compared with their production from common sugars.     

Natural cellulose fibers from soybean straw

This paper reports the development of natural cellulose technical fibers from soybean straw with properties similar to the natural cellulose fibers in current use. About 220 million tons of soybean straw available in the world every year could complement the byproducts of other major food crops as inexpensive, abundant and annually renewable sources for natural cellulose fibers. Using the agricultural byproducts as sources for fibers could help to address the concerns on the future price and availability of both the natural and synthetic fibers in current use and also help to add value to the food crops. A simple alkaline extraction was used to obtain technical fibers from soybean straw and the composition, structure and properties of the fibers was studied. Technical fibers obtained from soybean straw have high cellulose content (85%) but low% crystallinity (47%). The technical fibers have breaking tenacity (2.7 g/den) and breaking elongation (3.9%) higher than those of fibers obtained from wheat straw and sorghum stalk and leaves but lower than that of cotton. Overall, the structure and properties of the technical fibers obtained from soybean straw indicates that the fibers could be suitable for use in textile, composite and other industrial applications.     

Supplementation of watermelon peels as an enhancer of lipase and esterase production by Yarrowia lipolytica in solid-state fermentation and their potential use as biocatalysts in poly(ethylene terephthalate) (PET) depolymerization reactions

Abstract

Yarrowia lipolytica is a yeast that presents high biotechnological potential due to its ability to produce many metabolites, among them lipases and esterases, which are important industrial biocatalysts. Since Brazil is an agroindustrial country, it generates an enormous diversity of residues or byproducts that can be used as a platform for biomolecules production. This work aims to evaluate lipase and esterase production by Y. lipolytica via solid-state fermentation using soybean bran and soybean bran supplemented with watermelon peels in different contents, and subsequent use of the enzyme extracts for poly(ethylene terephthalate) (PET) hydrolysis. Supplementation of watermelon peels in the lowest content led to an improvement of lipase activity in almost 31%, reaching 75.22?U g^?1. Esterase productivity was 1.5-fold higher when 20?wt% of watermelon peels were added to the media culture. Timecourse evaluation of enzymes production showed a maximum lipase activity in 14?h and similar esterase activity in 14 and 20?h of fermentation. Proteases production were also intensified in supplemented samples. Enzymes produced with 5?wt% watermelon peels supplementation led to higher terephthalic acid concentration (up to 42.02?µmol L^?1) during PET depolymerization. Results suggest a great potential of enzyme production in low cost fermentative media to act as biocatalysts in PET hydrolysis reactions.     

Exploring a new,soluble lipase for FAMEs production in water-containing systems using crude soybean oil as a feedstock

Performance of a new lipase from Novozymes (Callera Trans L) was studied for fatty acid methylesters (FAMEs) production. In order to reduce the costs of the industrial enzymatic biodiesel production process, the enzyme was used in its soluble form instead of the common immobilized preparations. Cost reduction was also achieved by using crude (non-degummed) soybean oil as a cheaper raw material. The effect of water content during Callera Trans L-catalyzed FAMEs production was explored from evaluation of free fatty acids (FFAs), tri- di or monoacylglycerides (TAGs, DAGs, MAGs) variation during 24 h reaction. An excellent 96% FAMEs release was achieved when low (3–5%) water concentrations were used in the conversion of crude soybean oil. Time course HPLC analysis of the reaction products suggests that the soluble enzyme proceeds through a mechanism of methylester formation based on a first hydrolysis step that releases FFAs, DAGs or MAGs, followed by esterification of FFAs with methanol for FAMEs production.     

大豆异黄酮的微生物转化

大豆异黄酮是近年来发现的具有多种生物学活性的大豆营养成分。综述了微生物对大豆异黄酮的转化过程,对大豆异黄酮的生物利用和营养成分的影响,指出在富含大豆异黄酮类制品生产过程中合理利用微生物活动的重要意义和可能途径。     

Improvement of bacterial cellulose production by manipulating the metabolic pathways in which ethanol and sodium citrate involved

Nowadays, bacterial cellulose has played more and more important role as new biological material for food industry and medical and industrial products based on its unique properties. However, it is still a difficult task to improve the production of bacterial cellulose, especially a large number of byproducts are produced in the metabolic biosynthesis processes. To improve bacterial cellulose production, ethanol and sodium citrate are added into the medium during the fermentation, and the activities of key enzymes and concentration of extracellular metabolites are measured to assess the changes of the metabolic flux of the hexose monophosphate pathway (HMP), the Embden–Meyerhof–Parnas pathway (EMP), and the tricarboxylic acid cycle (TCA). Our results indicate that ethanol functions as energy source for ATP generation at the early stage of the fermentation in the HMP pathway and the supplementation of ethanol significantly reduces glycerol generation (a major byproduct). While in the EMP pathway, sodium citrate plays a key role, and its supplementation results in the byproducts (mainly acetic acid and pyruvic acid) entering the gluconeogenesis pathway for cellulose synthesis. Furthermore, by adding ethanol and sodium citrate, the main byproduct citric acid in the TCA cycle is also reduced significantly. It is concluded that bacterial cellulose production can be improved by increasing energy metabolism and reducing the formation of metabolic byproducts through the metabolic regulations of the bypasses.     

大豆根茬腐解产物的鉴定及化感作用的初步研究

采用ＧＣ－ＭＳ分析法鉴定了培养试验获得的大豆茬腐解２周、４周产生的有机化合物的酸、碱性组分产物,并对腐解２周、４周、８周各组分产物进行了化感作用的研究。结果表明：大豆根茬腐解产物（含微生物菌源根际土中的有机化合物）十分丰富,有酸类、酯类、醇类、醛类、酚类、烃类等物质,其中有些有机化合物已被研究证明是化感物质,还有些未见报道;不同腐解时间产生的有机化合物有一定差异;对腐解决物进行生物检测试验,发现大     

Conversion of sucrose into isomaltulose by Enterobacter sp. FMB1, an isomaltulose-producing microorganism isolated from traditional Korean food

Over 500 microorganisms isolated from Korean traditional foods, Maeju (source of soybean paste) and Nuruk (Korean koji), were screened to obtain an isomaltulose-producing microorganism. It was identified as Enterobacter sp. FMB-1 by 16S rRNA sequencing and the API 20E system. It had a greater than 90% conversion of sucrose (as 4 g/l) to isomaltulose in 2 days. Small amounts of trehalulose, glucose, and fructose were produced as byproducts, implying that this strain could be possibly employed in the production of isomaltulose in industry.     

Allocation procedure in ethanol production system from corn grain i. system expansion

We investigated the system expansion approach to net energy analysis for ethanol production from domestic corn grain. Production systems included in this study are ethanol production from corn dry milling and corn wet milling, corn grain production (the agricultural system), soybean products from soybean milling (i.e. soybean oil and soybean meal) and urea production to determine the net energy associated with ethanol derived from corn grain. These five product systems are mutually interdependent. That is, all these systems generate products which compete with or displace all other comparable products in the market place. The displacement ratios between products compare the equivalence of their marketplace functions. The net energy, including transportation to consumers, is 0.56 MJ_net/MJ of ethanol from corn grain regardless of the ethanol production technology employed. Using ethanol as a liquid transportation fuel could reduce domestic use of fossil fuels, particularly petroleum. Sensitivity analyses show that the choice of allocation procedures has the greatest impact on fuel ethanol net energy. Process energy associated with wet milling, dry milling and the corn agricultural process also significantly influences the net energy due to the wide ranges of available process energy values. The system expansion approach can completely eliminate allocation procedures in the foreground system of ethanol production from corn grain.     

Identification of quantitative trait loci contributing resistance to aflatoxin accumulation in maize inbred Mp715

Molecular Breeding - Soybean plays an important role in seed oil production for foods and industrial products in the USA. Chemical hydrogenation of commodity soybean oil increased functionality but...     

Biotransformation and recovery of the isoflavones genistein and daidzein from industrial antibiotic fermentations

The objective of this study was to follow the metabolic fate of isoflavone glucosides from the soybean meal in a model industrial fermentation to determine if commercially useful isoflavones could be harvested as coproducts from the spent broth at the end of the fermentation. The isoflavone aglycones, genistein, and daidzein together make up 0.1–0.2 % of the soybean meal by weight but serve no known function in the manufacturing process. After feeding genistein to washed cells of the erythromycin-producing organism, Saccharopolyspora erythraea, the first biotransformation product (Gbp1) was determined by X-ray crystallography to be genistein-7-O-α-rhamnoside (rhamnosylgenistein). Subsequent feeding of rhamnosylgenistein to growing cells of Saccharopolyspora erythraea led to the production of a second biotransformation product, Gbp2. Chromatographic evidence suggested that Gbp2 accumulated in the spent broth of the erythromycin fermentation. When the spent broth was hydrolyzed with acid or industrial enzyme preparations, the isoflavone biotransformation products were returned back to their parental forms, genistein and daidzein, which were then recovered as coproducts. Desirable features of this method are that it does not require modification of the erythromycin manufacturing process or genetic engineering of the producing organism to be put into practice. A preliminary investigation of five additional antibiotic fermentations of industrial importance also found isoflavone coproduct potential.     

EXTRACELLULAR LIPOLYTIC ENZYME ACTIVITY OF A NEWLY ISOLATED DEBARYOMYCES HANSENII

A strain isolated from waste of a milk products plant and exhibited extracellular lipolytic activity was identified as Debaryomyces hansenii by 5.8S rRNA and 28S rRNA gene sequence analyses. Lipolytic activity was assayed spectrophotometrically by using p-nitrophenylpalmitate. Higher specific lipolytic activities were obtained in the presence of tristearin (0.68 U/mg prot), oleic acid (0.56 U/mg prot), and soybean oil (0.36 U/mg prot) than other triglycerides, fatty acids, and vegetable oils considered as carbon sources. Cheese whey appeared to be a good alternative to lipidic substances for lipolytic activity. Among various organic and inorganic nitrogen sources, soy flour was found to attain the lipolytic activity similar to that provided by universal yeast medium components. This work is the first report on the discussion of lipolytic activity enhancement by D. hansenii through modulating the cultivation medium. It also proposes low cost medium nutrients that could be of industrial value and could serve as basal nutrients for further optimization studies on the lipase production by D. hansenii.     

Fish skin as a biomaterial for halal collagen and gelatin

Around 40% of the total catch weight of fish is regarded as byproducts, consisting of skin, fins, bones, scales, viscera, etc. The utilization of these byproducts is important to increase their commercial values as well as to prevent environmental pollution. Meanwhile, nowadays, it is getting a global trend to provide foods and other industrial materials which have been accredited as halal products for Moslem communities. As a way of processing fish byproducts to meet the halal criteria, preparation of collagen and gelatin would be useful to fulfill the market demand. As a result of screening studies on fishery byproducts, fish skin has been found to be the good source for halal collagen and gelatin, which show satisfactory quality compared with those from bovine sources which could cause bovine spongiform encephalopathy (BSE).     

Comparative processing practices of the world’s major oilseed crops

The major oilseed crops were domesticated primarily as sources of edible oil. However, in all cases, yields of by-products are greater than the oil fraction, and, in reality, all oilseed crops serve dual purposes as sources of oil and of protein for human food, animal feed, and industrial products. Each crop has special requirements for extraction and for processing of oil and meal, and each has limitations as to location and timing of production and as to processibility in oil mills originally designed for other crops. Further, each oilseed has unique cultural, economic and utilization characteristics; for example, rapeseed (Brassica) can be grown in cool climates with short growing seasons. Cottonseed (Gossypium) is a by-product of the more valuable fiber crop, and its availability is dictated by the profitability of growing cotton for the world market. Although peanuts (Arachis hypogaea) are used primarily as peanut butter and nuts in the United States, they are almost exclusively pressed for oil in other countries. In this paper, cultural practices and processing requirements of soybean (Glycine max), cottonseed, sunflower (Helianthus annuus), rapeseed, peanut, and sesame (Sesamum indicum) oils and byproducts are compared, as well as compositions of major oilmilling fractions, oils and proteins.     

Determination of bioactive compounds in fermented soybean products using GC/MS and further investigation of correlation of their bioactivities

The active ingredients and bioactivities (anti-oxidant, anti-tyrosinase, anti-proliferative and estrogenic activities) of soybean and soybean products (Cheonggukjang, Meju, Makjang, Doenjang and soy sauce) produced by different fermentation processes were compared. There were high correlations between active ingredients and bioactivities. Free phenolic acids extracted from soybean products were identified and quantified by gas chromatography/mass spectrometry (GC/MS). Overall, the components and activities in fermented soybean products were different than those in soybeans. Total phenolic content (TPC), protein content (PC) and anti-oxidant activity increased as fermentation time increased. TPC and PC showed strong negative correlations with anti-oxidant activity. Doenjang and soy sauce, two long-term fermented products, showed lower total flavonoid content (TFC) and estrogenic activities than short-term fermented soybean products. This might be explained by the decomposition and hydrolysis of flavonoids due to the long fermentation time and high temperature. Strong anti-proliferative activity against cancer cell lines, which was highly correlated with TFC, was found in Meju and Cheonggukjang. Soybean and all fermented products except Meju exhibited effective tyrosinase inhibitory activities. Fermented products showed stronger estrogenic activity than soybeans, which was highly correlated with syringic acid.     

Phenazine-1-carboxylic acid production in a chromosomally non-scar triple-deleted mutant Pseudomonas aeruginosa using statistical experimental designs to optimize yield

We constructed a non-scar triple-deleted mutant Pseudomonas aeruginosa to improve phenazine-1-carboxylic acid (PCA) yield and then optimized the culture conditions for PCA production. Using a non-scar deletion strategy, the 5′-untranslated region of the phz1 gene cluster and two genes, phzM and phzS, were knocked out of the P. aeruginosa strain M18 genome. The potential ability for high-yield PCA production in this triple-deleted mutant M18MSU1 was successfully realized by using statistical experimental designs. A 2^5–1 fractional factorial design was used to show that the three culture components of soybean meal, corn steep liquor and ethanol had the most significant effect on PCA production. Using a central composite design, the concentration of the three components was optimized. The maximum PCA production was predicted to be 4,725.1 mg/L. With the optimal medium containing soybean meal 74.25 g/L, corn steep liquor 13.01 g/L and ethanol 21.84 ml/L, a PCA production of 4,771.2 mg/L was obtained in the validation experiments, which was nearly twofold of that before optimization and tenfold of that in the wild-type strain. This non-scar triple-deleted mutant M18MSU1 may be a suitable strain for industrial production of this biologically synthesized fungicide due to its high PCA production, presumed safety, thermal adaptability and cost-effectiveness.     

Modeling of an industrial alcohol fermentation and simuiation of the plant by a process simulator

The aim of the present study was the development of a general simulation module for fermentation within the framework of existing chemical process simulators. This module has been applied to an industrial plant which produces ethanol from beet molasses and fresh beet juice by Saccharomyces cerevisiae. An unstructured mechanistic model has been developed with kinetic laws that are based on a chemically defined reaction scheme which satisfies stoichiometric constraints. This model can be applied to different culture conditions and takes into account secondary byproducts such as higher alcohols. These byproducts are of prime importance and need to be correctly estimated because a sequence of distillation columns follow the fermentor in the plant. Important measurement campaigns have been performed on the plant to validate the model. Plant operation has been successfully simulated using the same kinetic model for both continuous and fed-batch modes of production. (c) 1995 John Wiley & Sons, Inc.     

Ion exchange resins as catalyst for the isomerization of alpha-pinene to camphene

Camphene is an industrial intermediate compound for commercial chemicals such as isoborneol, isobornyl acetate and camphor. Industrially, the conventional process for camphene production consists of the isomerization of alpha-pinene using acidic TiO2 as catalyst. The use of this catalyst presents problems such as considerable time for preparation, reproducibility and recovery of catalyst from products after the alpha-pinene isomerization. For the first time, a commercial exchange resin was used as catalyst for this reaction. Based on the concentration of product as a function of the reaction time, the path of the alpha-pinene transformation to camphene and byproducts is proposed. Temperature and alpha-pinene/catalyst ratio were studied in order to optimize the yield to camphene production. The obtained results were comparable with those reported for acidic TiO2.     

Production of high molecular weight pullulan by Aureobasidium pullulans HP-2001 with soybean pomace as a nitrogen source

The production of pullulan by Aureobasidium pullulans HP-2001 was enhanced by yeast extract as a nitrogen source as well as soybean pomace. The highest production of pullulan by A. pullulans HP-2001 with yeast extract was 5.5 g/l whereas that of pullulan with soybean pomace was 7.5 g/l. The gas chromatogram of pullulan produced by A. pullulans HP-2001 with soybean pomace as a nitrogen source showed that the major and minor components were glucose and mannose. The FTIR spectra of pullulans produced with yeast extract, a mixture of yeast extract and soybean pomace, and soybean pomace alone exhibited similar features. The increase in content of reducing sugars after pullulanase treatment of pullulans produced with different nitrogen sources indicated that all the pullulans had alpha-(1,6) glucosidic linkages of alpha-(1,4) linked maltotriose units. The average molecular weights of pullulans produced with various concentrations of yeast extract and soybean pomace ranged from 0.17 to 1.32x10(6) and from 1.32 to 5.66x10(6), respectively. All pullulans produced by A. pullulans HP-2001 in this study had the same basic structures, but their ratios of monomeric components were a little different, which might result in the production of pullulans with different molecular weights.     

In silico aided metabolic engineering of Klebsiella oxytoca and fermentation optimization for enhanced 2,3-butanediol production

Klebsiella oxytoca naturally produces a large amount of 2,3-butanediol (2,3-BD), a promising bulk chemical with wide industrial applications, along with various byproducts. In this study, the in silico gene knockout simulation of K. oxytoca was carried out for 2,3-BD overproduction by inhibiting the formation of byproducts. The knockouts of ldhA and pflB genes were targeted with the criteria of maximization of 2,3-BD production and minimization of byproducts formation. The constructed K. oxytoca ΔldhA ΔpflB strain showed higher 2,3-BD yields and higher final concentrations than those obtained from the wild-type and ΔldhA strains. However, the simultaneous deletion of both genes caused about a 50 % reduction in 2,3-BD productivity compared with K. oxytoca ΔldhA strain. Based on previous studies and in silico investigation that the agitation speed during 2,3-BD fermentation strongly affected cell growth and 2,3-BD synthesis, the effect of agitation speed on 2,3-BD production was investigated from 150 to 450 rpm in 5-L bioreactors containing 3-L culture media. The highest 2,3-BD productivity (2.7 g/L/h) was obtained at 450 rpm in batch fermentation. Considering the inhibition of acetoin for 2,3-BD production, fed-batch fermentations were performed using K. oxytoca ΔldhA ΔpflB strain to enhance 2,3-BD production. Altering the agitation speed from 450 to 350 rpm at nearly 10 g/L of acetoin during the fed-batch fermentation allowed for the production of 113 g/L 2,3-BD, with a yield of 0.45 g/g, and for the production of 2.1 g/L/h of 2,3-BD.