The invention discloses an enzyme-method esterification deacidification technology for rice bran oil with a high acid value. The technology comprises the following steps: step one, obtaining rice bran oil with a high acid value; step two, carrying out enzyme-method esterification deacidification: heating the rice bran oil obtained in the step one under stirring in vacuum, adding glycerin and Lipozyme 435 immobilized lipase, carrying out esterification reactions between rice bran oil and glycerin in the presence of Lipozyme 435 immobilized lipase so as to obtain the de-acidified rice bran oil; step three, obtaining rice bran oil with a low acid value. In the provided technology, under a certain vacuum degree and temperature, the Lipozyme 435 immobilized lipase is used to catalyze the esterification reactions between the free aliphatic acids in rice bran oil with a high acid value and the glycerin so as to reduce the content of the free aliphatic acids, and thus the acid value of the rice bran oil can be reduced to below 3 mgKOH/g. The provided technology has the advantages of safety, environment-friendliness, low cost, and high refining yield, and is suitable for being applied to edible oil production.

Enzyme-method esterification deacidification technology for rice bran oil with high acid value

Nitrate reducing potency of 88 bacterial isolates segregated from marine and brackish water nitrifying bacterial consortia (NBC), generated for activation of nitrifying bioreactors, was confirmed by determining the nitrate reducing capability under aerobic conditions as maintained in nitrifying bioreactors. All the isolates had the potential to be used as bio-augmentors for activating nitrate dissimilation in recirculating aquaculture system. The existence of nitrate reducers with nitrifiers in NBC and in the reactor configuration negates the requirement of integrating anoxic denitrifying system for effective removal of NO3−-N. Phylogenetic analyses of representative isolates from each cluster of the dendrograms generated based on phenotypic characterization and amplified ribosomal DNA restriction analysis revealed profound diversity of nitrate reducing bacterial flora in the NBC. They were composed of Streptomyces enissocaesilis, Marinobacter sp., Pseudomonas sp., Microbacterium oxydans, Pelagibacterium halotolerans and Alcanivorax dieselolei from marine NBC and Streptomyces tendae, Nesterenkonia sp., Bacillus cereus, Microbacterium oxydans and Brevibacterium sp. from brackish water NBC. The diversity indices of the consortia were calculated using Mega 5.0, primer 7 and VITCOMIC softwares. Marine NBC exhibited higher Shannon wiener diversity and mean population diversity than brackish water NBC. The study delineated higher species richness and diversity in marine NBC than in its brackish water counterpart, a possible reflection of the higher biodiversity of marine systems, and hence, the former is more promising to be used as start-up cultures for the activation of nitrifying bioreactors after appropriate acclimatization to the desired salinity.

Genetic diversity of nitrate reducing bacteria in marine and brackish water nitrifying bacterial consortia generated for activating nitrifying bioreactors in recirculating aquaculture systems

The invention discloses a rice bran oil deacidification process based on an enzyme method, which is characterized by performing esterification reaction on endogenous phytosterin in rice bran oil (optionally, plus a certain amount of phytosterin (phytosterol)) and free fatty acid in the high-acid-value rice bran oil under the catalytic action of lipase to reduce the acid value of the rice bran oil, thus obtaining a grease product containing phytosterin (phytosterol) fatty acid ester. The method comprises the following steps: mixing rice bran oil, phytosterin (phytosterol) and optional organic solvent ( n-hexane or acetone) according to a certain ratio until the phytosterin (phytosterol) is completely dissolved; proportionally adding lipase, performing enzyme reaction at certain temperature for certain time in an intermittent and semicontinuous reactor until the acid value of the rice bran oil is reduced to 4mg KOH/g or below, and stopping the reaction; and performing subsequent processing: removing and recovering the organic solvent, performing cooling crystallization to remove and recover the unreacted phytosterin (phytosterol), and recovering the lipase, a molecular sieve and the organic solvent for recycling.

Rice bran oil deacidification process based on enzyme method

The present invention relates to a refined vegetable oil as well as a method of producing it. The method uses the combination of a polyol-containing solvent, such as glycerol, and an alkalizing agent for selectively extracting free fatty acids from the vegetable oil.

Refined vegetable oil and a method of producing it

The invention belongs to the field of edible oil processing, in particular to a method for dry degumming and refining of edible rice bran oil. The dry degumming utilizes the mixing and flocculation of phosphoric acid and gum impurities to form larger particles so as to facilitate to remove out of oil by filter after the larger particles are mixed with waste clay. The secondary decolorization absorbs and removes pigments formed in physical deacidification and original pigments in oil by utilizing the adsorption of the clay to the pigments. The deordorization utilizes a steam distillation principle, i.e., under high vacuum and certain temperature, direct steam is pumped into the oil to reduce the partial pressure of odor substances in the oil, so that the substances are gasified and discharged from the oil along with the steam, and thereby, the oil has no peculiar smell. The invention has no water adding hydration process and no oil sediment and waste water, and the product yield can beincreased by more than 3%; the secondary decolorization is adopted, and the color is good; the deodorization process is added, the oil has no peculiar smell; and the second dewaxing process is adopted, the wax content in the oil is extremely low, and the oil quality is improved.

Method for dry degumming and refining of edible rice bran oil

The invention relates to an esterification deacidification process for high acid number rice bran oil, and the process can well solve the problem of a low refining rate. The esterification deacidification process for high acid number rice bran oil comprises grease pretreatment, namely two steps of degumming and decolorizing. A decolorized substance is obtained after the decolorizing, and then esterification deacidification is carried out. The concrete operating method comprises the following steps of: adding glycerin after the decolorized substance is stirred and heated at a vacuum degree of 0.09 MPa; adding a catalyst of zinc oxide or zinc to carry out a catalytic reaction to generate low acid number rice bran oil with an acid number of 5-7mgKOH/g. The zinc oxide or zinc which is taken as the catalyst of the esterification deacidification of the high acid number bran oil can effectively boost the esterification reaction and rapidly reduce the acid number; simultaneously the process overcomes the problems of the low refining rate lying in a traditional refining method and a great deal of sewage produced by a chemical alkali refining method; the zinc oxide or zinc has a low price, thereby reducing production cost; compared with other chemical esterification catalysts, the zinc oxide or zinc has a very low toxity, thereby being very suitable for the production of edible grease.

High-acid value rice bran oil esterification depickling process

Combining eDNA and morphological approaches to reveal the impacts of long-term discharges of shale gas wastewaters on receiving waters.

OBJECTIVE In order to improve the rate of the heterotrophic nitrification, we screened and identified a high-efficient heterotrophic nitrifier, as well as studied its nitrification characteristics and nitrification conditions. METHODS We obtained activated sludge samples from sewage and chemical fertilizer factories and farmland. We then utilized sodium citrate and ammonium chloride as carbon and nitrogen source. We used methods including domestication, gradient dilution of domestication liquid, isolation from streaking plate and color indicator as rapid nitrification detection. Finally a high-efficient heterotrophic nitrifier was obtained. We identified this strain according to its physiological, biochemical properties and the sequence analysis of 16S rDNA. After inoculating the strain into artificial ammonia-nitrogen wastewater, changes of nitrogen compounds were measured in order to understand the nitrification characteristics. Nitrification condition was also optimized by changing the carbon source, dissolved oxygen, C/N ratio, temperature and pH of the medium. RESULTS The heterotrophic nitrifier was a gram-negative bacilli. It neither fermented glucose, nor produced indole. Oxidase and catalase tests were positive. It could produce alkali if organic salt was provided. The strain shared 99.7% sequence identity of its 16S rDNA with ES-SDK-3 of Alcaligenes sp. In the artificial wastewater with 182.30 mg/L ammonia nitrogen as initial concentration, the removal efficiency by the strain was 99. 8% after 30h cultivation. The average nitrogen removal rate was 9. 61 mg-N/L/h in its exponential phase. It produced almost no NO(2-)-N and NO(3-)-N in the entire nitrification process. The optimal carbon source is sodium citrate. Higher dissolved oxygen and C/N ratio favor its nitrification. When temperature is ranged from 30 degrees C to 35 degrees C and pH is ranged from 5.0 to 9.0, it can completely remove ammonia nitrogen. CONCLUSIONS The strain was identified as Alcaligenes genus, and named as Alcaligenes sp. HN-S. Our research confirmed that the Alcaligenes sp. HN-S had significant advantages over heterotrophic nitrifiers that were screened previously with aspect of ammonia nitrogen removal rate. The research of its nitrification condition definitely provided necessary theory support for a new biology process to remove nitrogen with high efficiency.

Zhiqiang Li

Papers

High-acid value rice bran oil esterification depickling process

Combining eDNA and morphological approaches to reveal the impacts of long-term discharges of shale gas wastewaters on receiving waters.

[Isolation, identification and characterization of a high-efficient heterotrophic nitrifier].

River Water Influenced by Shale Gas Wastewater Discharge Used for Rice Irrigation Has Limited Effects

River water influenced by shale gas wastewater discharge for paddy irrigation has limited effects on soil properties and microbial communities.