Current Biotechnology

Suggestions to Speed Up the Development of Cellulosic Ethanol Industry in China
LIU Yue, DU Feng-guang
2014, 4(5): 305-309. DOI: 10.3969/j.issn.2095-2341.2014.05.01
Abstract ( ) PDF (1067KB)( )

With the continuous growth of China’s car ownership，vehicle emissions has become one of the important factors that affect air quality. Cellulosic ethanol, with the superiority of being a kind of green， environmentally friendly and renewable resource，can contribute to promote combustion and to reduce emissions. This paper summarized the importance and necessity of developing cellulosic ethanol industry considering from the national energy security，food security，farmers’ income， environmental pollution and other aspects. Meanwhile，combined with the current development status of cellulosic ethanol industry，this paper also proposed policy recommendations for cellulosic ethanol industry.

Application of Transgenic Technology in Energy Plant Breeding
AN Fu-rong1, DAI Li-chun1, Wu Bo1, QIN Han1, ZHU Qi-li1, WANG Wen-guo1, TANG Xiao-yu1, PAN Ke1, SU Hai-feng1, HU Qi-chun1,2, HE Ming-xiong1,2*
2014, 4(5): 310-317. DOI: 10.3969/j.issn.2095-2341.2014.05.02
Abstract ( ) PDF (1171KB)( )

Due to the increasingly serious of energy crisis and environmental pollution problems，energy plants，for its characteristics of safety, environmental friendly，renewable and low cost，has become a hotspot of energy exploitation. With the continuous advancement of transgenic technology，the use of transgenic technology to cultivate high\|yield，high quality, efficient energy plant new varieties has made the corresponding results. This paper briefly introduced the concept of energy plants and classification，and outlined the application status of transgenic technology in increasing total biomass of plants, reducing plant lignin content，overexpressing cellulose degrading enzymes in plants，increasing oil content of oil plants and other aspects. The prospect of energy plant improvement using transgenic technology was also discussed，with the aim to provide references for future energy plant genetic engineering breeding research and its application.

Research Progress in Biotechnological Applications of Oil Bodies
YAO Zheng-ying, ZHANG Wei-ming, SUN Li-jun*
2014, 4(5): 318-324. DOI: 10.3969/j.issn.2095-2341.2014.05.03
Abstract ( ) PDF (1161KB)( )

Oil bodies are the important oil storage organelles in plant seeds， particularly in oil plant seeds. Oil bodies have strong physical and chemical stability and are easily separated by centrifugation. Studies showed that oil bodies have a spherical or ellipsoid shape and are composed of outer phospholipid, integral proteins and inner liquid matrix (mostly triacylglycerol). To date，three types of integral proteins have been found in plants and are mainly localized on the surface of oil bodies. In view of the unique structures of oil bodies and integral proteins，both of them have been widely applied in the field of biotechnology. This review summarized advantages and strategies of using oil bodies in expression and purification of recombinant proteins，as well as its applications in the fields of production of pharmaceutical protein，preparation of immobilized enzymes，affinity capture of antibodies and pharmaceutical enzymes，production of nutraceuticals，enhancement of plant resistance against pathogen. The development and applications of artificial oil bodies and oil-body-emulsifying-agents were also discussed.

Progress in Technology of Separation and Extraction for Biobutanol
LIU Xiao-jie1,2, SHEN Zhao-bing1,2, ZHANG Li-li1,2, LIU Li1,3*, SHI Ji-ping1*
2014, 4(5): 325-330. DOI: 10.3969/j.issn.2095-2341.2014.05.04
Abstract ( ) PDF (1105KB)( )

This paper reviewed current application research and status of separation and extraction technologies for biobutanol，including liquid-liquid extraction，gas stripping，adsorption，distillation and pervaporation. Advantages and limitations in each separation method were also presented，meanwhile，separation results and performance among those methods were compared. Finally the development prospects of biobutanol separation and extraction technologies were proposed.

Research Progress of Zymomonas mobilis on Biorefinery System
2014, 4(5): 331-339. DOI: 10.3969/j.issn.2095-2341.2014.05.05
Abstract ( ) PDF (1223KB)( )

Biorefinery technologies using lignocellulosic biomass as feedstock have become a hot topic and huge task in globle research and development，which are also an important goal of long\|term biomass energy roadmap in both EU countries and the United States. However，the current overall level is still in pilot stage. China has abundant biomass resources，which has great potential in the production of biomass energy and bio\|based chemicals，but also faces a lot of bottleneck problems to be solved in order to achieve commercial production. The lack of efficient fermentation strains simultaneously ferment cellulosic hydrolyzate，has become a key constraint in cellulosic biorefinery. Currently，Zymomonas mobilis has became a preferred host in cellulosic ethanol fermentation for its unique ED pathway. Z. mobilis also showed some advantages of higher specific rate of sugar uptake，etc.，which made it an ideal platform for commercial\|scale production of desirable bio\|products，such as sorbitol，gluconic acid，succinic acid and isobutanol. This paper reviewed the research history，molecular biology，strain improvement and its application in biorefinery system, and also put forwards that Z. mobilis could be considered as a noval important microbe platform of cellulosic biomass biorefinery system.

Progress on Thermophilic β-Mannanase
WANG Cai-hong, NIU Can-fang, LUO Hui-ying*, YANG Pei-Long, YAO Bin
2014, 4(5): 340-345. DOI: 10.3969/j.issn.2095-2341.2014.05.06
Abstract ( ) PDF (1121KB)( )

β-Mannanase has important application prospect in bioenergy，feed， food，textile and other industries. β-Mannanase which belongs to hemicellulose enzymes exists in a wide variety of plants，animals and especially in microorganisms. With the extensive research of extremophiles and extreme enzymes，thermophilic mannanases receive much concern because of their high enzyme activity and stability at high temperature. This paper reviewed the source and classification of β-mannanases and the hydrolysis pattern of thermophilic β-mannanase，as well the gene cloning，expression and molecular improvement. The research orientation and development prospects were also elucidated in this paper.

Progress of Reutilization of Seafood Processing Waste
GAO Xiu-jun, YAN Pei-sheng*
2014, 4(5): 346-354. DOI: 10.3969/j.issn.2095-2341.2014.05.07
Abstract ( ) PDF (1189KB)( )

Application of biotechnology for reutilization of seafood processing wastes has been increasingly concerned by researchers all over the world. Fully reutilization of these by-products can recycle waste resources and protect environment, as well as bring us enormous economic benefit. This paper reviewed on present situation and problems of reutilization of seafood processing wastes, summarized the progress of biotechnology application in reutilization of seafood processing wastes, and prospected the future development trends.

Progress on Microbial Technology for Removal of Antibiotics Residues Pollution
ZHANG Xin-yang, XU Xu-ping*
2014, 4(5): 355-360. DOI: 10.3969/j.issn.2095-2341.2014.05.08
Abstract ( ) PDF (1104KB)( )

Antibiotics in the environment will have a profound impact on orgnisms. Removal of antibiotic residues cause for concern in many countries. Since antibiotics in the environment are mainly biodegradable，and resistant strains of microorganisms play the most important effect，the use of microbial technology in treatment of antibiotics residues contamination becomes a hot topic in recent years. This paper summarized the microbial resources for degradation of antibiotics and the biotechnology of using composite processing strains for removal of antibiotics，then discussed the deficiencies and development directions of microbial treatment technology.

Butanol Production from Corn Fiber Using Clostridium beijerinckii NCIMB 8052
2014, 4(5): 361-367. DOI: 10.3969/j.issn.2095-2341.2014.05.09
Abstract ( ) PDF (1288KB)( )

Corn fiber, a byproduct of corn starch processing, is a potential unexpensive bioresource for butanol production. Butanol production from corn fiber using Clostridium beijerinckii NCIMB 8052 was investigated in this study. Corn fiber was firstly pretreated by 0.5% sulfuric acid with solid\|to\|liquid ratio of 1：8 for 20 min under the optimal temperature 140℃，followed by enzymatic hydrolysis at glucoamylase loading of 200 IU/g（dry material）and xylanase loading of 1.0 IU/g （dry material）. The starch and hemicellulose were mostly hydrolyzed into fermentable sugars including glucose，xylose and arabinose，resulting in a total fermentable sugars concentration of 50.46 g/L. Then the hydrolysate of corn fiber was detoxified by 1.0% active carbon in order to remove the inhibitors of butanol fermentation. Batch fermentation using the detoxified hydrolysate of corn fiber showed that 9.72 g/L of butanol and 14.09 g/L of total solvents were produced at the end of the fermentation period，and the sugar-to-solvents ratio was 35.1%. These results above suggested that it is a feasible strategy for butanol production by corn fiber fermentation using Clostridium beijerinckii NCIMB 8052.

Study on the Separation and Extraction Technology of Gamma-aminobutyric Acid (GABA) for PA4
ZHAO He-fei, XIA Quan-ming, QIU Yong-jun, WANG Yao-song, JIANG Li-hua, ZHAO Li-ming*
2014, 4(5): 368-372. DOI: 10.3969/j.issn.2095-2341.2014.05.10
Abstract ( ) PDF (1947KB)( )

In order to explore the extraction technology of GABA from fermentation broth with glutamic acid as substrate, membrane filtration associated with ion\|exchange adsorption and desorption process were studied in this paper, and followed with decolorization by using active carbon. The initial trans\|membrane pressure is 0.85 bar during the filtration process, and the temperature was controlled at 38℃. With QY-021-a strong acid cation exchange resin as packing in ion\|exchange column, adsorption-desorption process was exerted at room temperature. After concentrated by rotary evaporation, decolorization was performed using 15% (carbon/solids in the solution) activate carbon, with temperature fixed at 65℃, stirring for 40 min. Results showed that the average flux was 128 L/m2·h, and concentration ratio was 33.3. Samplings to detect membrane permeate showed that the yield of GABA was 97.7%, which indicated that there was no GABA retention of interception and adsorption on microfiltration membrane surface and fouling layer. After collecting 5 BV permeate to calculate the yield of ion-exchange process, results showed that the yield was 92.8%, decolorization ratio was 94.2% by using activate carbon B, and the GABA yield was 99.2%. The total yield of the whole process was up to 85%, which indicated that this process has the prospects for industrial application, and further improvements of yield could be achieved by optimized ion exchange processes and equipment.

Production of Ricinoleic Acid from Castor Oil by Free Lipase-mediated Hydrolysis
YANG Wei, DU Wei*, LIU De-hua
2014, 4(5): 373-378. DOI: 10.3969/j.issn.2095-2341.2014.05.11
Abstract ( ) PDF (1302KB)( )

Compared to immobilized lipase, free lipase has the merits of lower cost and faster reaction rate, which is a rising research orientation in oil chemical industry. The previous study showed that free lipase NS81006 is capable of efficiently hydrolyzing oil to fatty acids. Further study on its unique hydrolysis process of castor oil, an environmentally friendly hydroxyl oil, is of great importance for its application in new energy. By means of optimizing the main influence factors of the castor oil hydrolysis catalyzed by NS81006 involving temperature, enzyme dosage, water usage, and stirring speed, 98.4% degree of hydrolysis was achieved under the optimum conditions at 48 h. The free lipase could be reused after centrifugation and maintained high catalytic efficiency in 5 consecutive recovery batches. It was also found that enzyme catalysis has obvious advantage in castor oil hydrolyzation compared with HTHP.

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