editorial microbial enzymes and their applications...

EditorialMicrobial Enzymes and Their Applications inIndustries and Medicine 2014

Periasamy Anbu,1 Subash C. B. Gopinath,2 Bidur Prasad Chaulagain,3

Thean-Hock Tang,4 and Marimuthu Citartan4

1Department of Biological Engineering, College of Engineering, Inha University, Incheon 402-751, Republic of Korea2Institute of Nano Electronic Engineering (INEE) and School of Bioprocess Engineering, Universiti Malaysia Perlis,01000 Kangar, Perlis, Malaysia3Department of Microbiology, Molecular Biology and Biotechnology, Himalayan College of Agricultural Sciences andTechnology (HICAST), P.O. Box 25535, Kalanki, Kathmandu, Nepal4Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia, 13200 Kepala Batas, Penang, Malaysia

Correspondence should be addressed to Periasamy Anbu; [email protected]

Received 3 May 2015; Accepted 3 May 2015

Copyright © 2015 Periasamy Anbu et al.This is an open access article distributed under theCreativeCommonsAttribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Production of microbial enzymes is a necessary event inthe industrial sectors, due to the high and superior perfor-mances of enzymes from different microbes, which workswell under a wide range of varied physical and chemicalconditions. Microbial enzymes serve as a potential replace-ment, in absence or insufficiency of human enzymes. Further,microbial enzymes are the preferred source of industrialenzymes as they can be produced in large quantities in ashort period of time and have shorter generation times,and genetic manipulations can be performed more easily onbacterial cells to increase the enzyme production. Still theindustries are looking for new microbial strains in order toproduce different enzymes to fulfill the enzyme requirements.This special issue covers ten articles including two reviewarticles, highlighting the importance and applications ofbiotechnologically relevant microbial enzymes.

In the work carried out by J. R. Wang et al., they haveoptimized the codonusage in order to enhance the expressionlevel of 𝛼-amylase gene from Bacillus licheniformis in Pichiapastoris. A total of 328 nucleotides were altered and theG + C content was improved from 47.6 to 49.2%. Theoptimized gene has demonstrated a higher level of expressionin P. pastoris after methanol induction for 168 h in 5- and50-L bioreactor with the maximum activity of 8100 and11000U/mL, compared to the wild type by 2.31- and 2.62-fold.The enzyme is viewed as a potential candidate for 𝛼-amylaseproduction in industrial use.

L. M. Colla et al. have carried out studies on thepartial characterization of lipase acquired from solid-statefermentation by the species of Aspergillus. The fungal strainsisolated from diesel contaminated soil and selected as theliapse producer. Two types of fermentation were adopted,whereby lipase produced from the submerged fermentationshowed an optimum activity at 37∘C and pH 7.2. In anotherfermentation mode, the solid-state fermentation, the optimaltemperature and pH for the solid-state fermentation are35∘C and pH 6.0, respectively. Out of the two fermentationmodes, lipase produced from the submerged fermentationhas more stability at higher temperature than the solid-statefermentation. Lipase from the submerged fermentation stillretains 72% of residual activity after one hour of exposure at90∘C. Furthermore, 80% of the residual activity is retainedat the acidic pH while lipase obtained from the solid-statefermentation results in residual activity of 60% at the alkalinepH.

N. E.-A. El-Naggar et al. have isolated L-asparaginaseproducing actinomycete from soil samples. In this study,the isolated strain was identified as Streptomyces olivaceusbased on the morphological, physiological, biochemical,and molecular analysis. Further, the enzyme productionwas optimized by response surface method to improve thelevel of enzyme synthesis. The authors have screened fifteenvariables using Plackett-Burman experimental design. Themost significant independent variables affecting enzyme pro-duction were further optimized by the face-centered central

Hindawi Publishing CorporationBioMed Research InternationalVolume 2015, Article ID 816419, 3 pageshttp://dx.doi.org/10.1155/2015/816419

2 BioMed Research International

composite design-response surface methodology. Finally, thestrainwas able to produce a significant level of L-asparaginaseenzyme in optimized media.

The review article by F. D. Inacio et al. focused onproteases of wood rot fungi with emphasis on the Pleurotusgenus. In this review article, the authors have highlighted thecharacteristics of the Pleurotus genus such as easy cultivationtechniques, high yield, low nutrient requirements, and itsadaptation. In addition, the authors have also highlighted theuses and applications of the proteases in various industriessuch as biotechnology and medicine.

Another study with amylase is by I. Ali et al.; theyperformed purification and characterization of polyex-tremophilic extracellular 𝛼-amylase from a halophilic strain,Aspergillus penicillioides, to be coused with detergents. Purifi-cation was performed by ammonium sulfate precipitationand Sephadex G100 gel filtration methods and the purifiedenzyme has an apparent molecular weight of 42 kDa. Thepurified enzyme showed higher specificity with the substrate,starch, with an optimal activity at pH 9, 80∘C in the presenceof NaCl and CaCl

2. Authors have shown retaining amylase

activity as 80% with different laundry detergents, claimed asbetter activity than commercial amylase.

The review article by S. C. B. Gopinath et al. is on thebiotechnological aspects of keratinase production and theirfuture perspectives in industries. Because of ever increasingindustrialized food and agriculture market there is highbiomass production of the tough biomass keratin which willbe biopollutant to the earth and needs to be addressed in amore ecofriendly way. The review highlights the productionof keratinase from reliable sources that can be easilymanaged.The authors put emphasis on microbial keratinase because itis less expensive and more precise than those conventionallyused chemicals to treat keratin. The paper discusses differentperspective of enzymatic keratinases which can be obtainedfrom fungi, bacteria, and actinomycetes. The attraction tothis article for readers is due to the expansion of infor-mation on various aspects of keratinase like descriptionson keratinophilic fungi, keratin-degrading bacterial isolates,secretion of microbial keratinases, optimization of keratinaseactivities, purification process, accelerating microbial ker-atinase production through biotechnological approach, anddeveloping keratinase sensing technologies in future.

In the article by A. Badhan et al., they have utilizedenzyme fingerprinting to identify cell wall componentsresistant to total tract digestion. Acetyl xylan esteraseswere identified as the key component to the improvedruminal digestion. Polysaccharide-lignin cross-linked cellwall polymers were identified as the principal componentsindigested fiber residues in the feces. Enzyme pretreatmentwas carried out following the analysis of the structuralinformation obtained from the enzymatic fingerprinting andFTIR to enhance glucose yield from barley straw and alfalfahay. Statistical experimental design was used to analyze theprehydrolysis effects of recombinant acetyl xylan esterases(AXE16B ASPNG and AXE16A ASPNG), polygalacturonase(PGA28A ASPNG), and 𝛼-arabinofuranosidase (ABF54BASPNG) all from Aspergillus niger, feruloyl esterase (FAE1a)from Anaeromyces mucronatus (expressed in E. coli), and

endoglucanase GH7 (EGL7A THITE) from Thielaviaterrestris (produced in Aspergillus niger). Degradation ofplant structural polysaccharides is inducted by the fungalfibrinolytic hemicellulases and auxiliary enzymes. Moreover,in vitro saccharification of alfalfa and barley straw bymixed rumen enzymes was improved. The model alsoestimated glucose yield that improves by 75% followingpretreatment with polygalacturonase (PGA28A ASPNG)and 𝛼-arabinofuranosidase (ABF54B ASPNG) in 1 : 1ratio. A hundred percent improvement was obtained afterprehydrolysis of barley straw with a mixture of EGL7ATHITE (50%) and FAE1a (50%). Microassay and statisticalexperimental design can be integrated to predict effectiveenzyme pretreatments that can enhance plant cell walldigestion by mixed rumen enzymes. This study also hasthe potential to develop specific enzyme pretreatments forforages, depending on their structure and composition.

B. K. Dash et al. have isolated a new Bacillus subtilisstrain (BI 19) from the soil and studied the molecular char-acterizations for the enhanced production of extracellularamylase. In their study, the phylogenetic tree was constructedon the basis of 16S rDNA gene sequences and revealed thatthis strain clustered with the closest members of Bacillussp. The effect of various fermentation conditions on amylaseproduction from this strain, through shake-flask culture, wasinvestigated. Rice flour was found to be a cheap naturalcarbon source to induce amylase production. In addition,a combination of peptone and tryptone as organic andammonium sulfate as inorganic nitrogen sources gave highestyield. Further, maximum production was obtained with thefollowing optimal conditions: 24 h of incubation, 37∘C, andpH 8.0. Further increments in the amylase productions werenoticed in the presence of Tween 80 and sodium laurylsulfate. Their results suggest that newly isolated B. subtilis BI19 could be exploited for industrial production of amylase atrelatively low cost and time.

S. G. Karp et al. on their original research report discussthe optimization of laccase production and its role in delig-nification. They have worked on the statistical optimizationof laccase production by a strain of Pleurotus ostreatus andits delignification properties of sugarcane bagasse. Withthe determination of the mathematical model of laccaseproduction through the response surface method they haveanalyzed the role of various factors and came to conclusionthat yeast extract as an organic nitrogen source is veryimportant along with appropriate concentration of coppersulfate and ferulic acid and the incubation period in solid-state fermentation for the delignification of sugar bagasse.The authors are successful in reducing the lignin content ofsugar bagasse around one-third to one-fourth of the originallignin biomass. Such kind of experiment is important fordelignification of biomass for future use in other industrialapplications like production of biobased fuel to other organicproducts like food and beverages to paper and textile indus-tries. The advantages of enzymatic delignification over theconventional physicochemical methods will be less healthhazardous to ecosystem in future. The other advantages oflaccase enzyme optimization may include relatively higherproduct yields and fewer side reactions and increased reactor

BioMed Research International 3

efficiency due to mild reaction conditions and lesser energyrequirements.

L. P. Lee et al. have isolated many Bacillus species fromoil spillage area in Malaysia. In this study, the isolated strainswere screened for lipase and protease enzymes using lipidand gelatin, respectively, as the substrates. In addition, thecomparison analyses of lipase and protease activities werealso analyzed. The result showed that most of the strainswere able to produce both enzymes at significant levels. Thesimultaneous secretion of both the lipase and protease is ameans of survival. The isolated Bacillus species which harborlipase and protease enzymes could render potential industrialbased applications and solve the environmental problems.

Periasamy AnbuSubash C. B. Gopinath

Bidur Prasad ChaulagainThean-Hock Tang

Marimuthu Citartan

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