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Fulltext Communal microaerophilic-aerobic biodegradation of Amaranth by novel NAR-2 bacterial consortium

Chan GF, Rashid NA, Chua LS, Ab llah N, Nasiri R, Ikubar MR

Bioresour Technol, 2012 Feb;105:48-59.
PMID: 22182471 DOI: 10.1016/j.biortech.2011.11.094

A novel bacterial consortium, NAR-2 which consists of Citrobacter freundii A1, Enterococcus casseliflavus C1 and Enterobacter cloacae L17 was investigated for biodegradation of Amaranth azo dye under sequential microaerophilic-aerobic condition. The NAR-2 bacterial consortium with E. casseliflavus C1 as the dominant strain enhanced the decolorization process resulting in reduction of Amaranth in 30 min. Further aerobic biodegradation, which was dominated by C. freundii A1 and E. cloacae L17, allowed biotransformation of azo reduction intermediates and mineralization via metabolic pathways including benzoyl-CoA, protocatechuate, salicylate, gentisate, catechol and cinnamic acid. The presence of autoxidation products which could be metabolized to 2-oxopentenoate was elucidated. The biodegradation mechanism of Amaranth by NAR-2 bacterial consortium was predicted to follow the steps of azo reduction, deamination, desulfonation and aromatic ring cleavage. This is for the first time the comprehensive microaerophilic-aerobic biotransformation pathways of Amaranth dye intermediates by bacterial consortium are being proposed.

Matched MeSH terms: Industrial Microbiology/methods
Keratinase production and biodegradation of polluted secondary chicken feather wastes by a newly isolated multi heavy metal tolerant bacterium-Alcaligenes sp. AQ05-001

Yusuf I, Ahmad SA, Phang LY, Syed MA, Shamaan NA, Abdul Khalil K, et al.

J Environ Manage, 2016 Dec 01;183:182-95.
PMID: 27591845 DOI: 10.1016/j.jenvman.2016.08.059

Biodegradation of agricultural wastes, generated annually from poultry farms and slaughterhouses, can solve the pollution problem and at the same time yield valuable degradation products. But these wastes also constitute environmental nuisance, especially in Malaysia where their illegal disposal on heavy metal contaminated soils poses a serious biodegradation issue as feather tends to accumulate heavy metals from the surrounding environment. Further, continuous use of feather wastes as cheap biosorbent material for the removal of heavy metals from effluents has contributed to the rising amount of polluted feathers, which has necessitated the search for heavy metal-tolerant feather degrading strains. Isolation, characterization and application of a novel heavy metal-tolerant feather-degrading bacterium, identified by 16S RNA sequencing as Alcaligenes sp. AQ05-001 in degradation of heavy metal polluted recalcitrant agricultural wastes, have been reported. Physico-cultural conditions influencing its activities were studied using one-factor-at-a-time and a statistical optimisation approach. Complete degradation of 5 g/L feather was achieved with pH 8, 2% inoculum at 27 °C and incubation period of 36 h. The medium optimisation after the response surface methodology (RSM) resulted in a 10-fold increase in keratinase production (88.4 U/mL) over the initial 8.85 U/mL when supplemented with 0.5% (w/v) sucrose, 0.15% (w/v) ammonium bicarbonate, 0.3% (w/v) skim milk, and 0.01% (w/v) urea. Under optimum conditions, the bacterium was able to degrade heavy metal polluted feathers completely and produced valuable keratinase and protein-rich hydrolysates. About 83% of the feathers polluted with a mixture of highly toxic metals were degraded with high keratinase activities. The heavy metal tolerance ability of this bacterium can be harnessed not only in keratinase production but also in the bioremediation of heavy metal-polluted feather wastes.

Matched MeSH terms: Industrial Microbiology/methods*
Fulltext Optimizing culture conditions for production of intra and extracellular inulinase and invertase from Aspergillus niger ATCC 20611 by response surface methodology (RSM)

Dinarvand M, Rezaee M, Foroughi M

Braz J Microbiol, 2017 Jul-Sep;48(3):427-441.
PMID: 28359854 DOI: 10.1016/j.bjm.2016.10.026

The aim of this study was obtain a model that maximizes growth and production of inulinase and invertase by Aspergillus niger ATCC 20611, employing response surface methodology (RSM). The RSM with a five-variable and three-level central composite design (CCD) was employed to optimize the medium composition. Results showed that the experimental data could be appropriately fitted into a second-order polynomial model with a coefficient of determination (R2) more than 0.90 for all responses. This model adequately explained the data variation and represented the actual relationships between the parameters and responses. The pH and temperature value of the cultivation medium were the most significant variables and the effects of inoculum size and agitation speed were slightly lower. The intra-extracellular inulinase, invertase production and biomass content increased 10-32 fold in the optimized medium condition (pH 6.5, temperature 30°C, 6% (v/v), inoculum size and 150rpm agitation speed) by RSM compared with medium optimized through the one-factor-at-a-time method. The process development and intensification for simultaneous production of intra-extracellular inulinase (exo and endo inulinase) and invertase from A. niger could be used for industrial applications.

Matched MeSH terms: Industrial Microbiology/methods*
Optimization of Culture Medium for the Growth of Candida sp. and Blastobotrys sp. as Starter Culture in Fermentation of Cocoa Beans (Theobroma cacao) Using Response Surface Methodology (RSM)

Mahazar NH, Zakuan Z, Norhayati H, MeorHussin AS, Rukayadi Y

Pak J Biol Sci, 2017;20(3):154-159.
PMID: 29023007 DOI: 10.3923/pjbs.2017.154.159

BACKGROUND AND OBJECTIVE: Inoculation of starter culture in cocoa bean fermentation produces consistent, predictable and high quality of fermented cocoa beans. It is important to produce healthy inoculum in cocoa bean fermentation for better fermented products. Inoculum could minimize the length of the lag phase in fermentation. The purpose of this study was to optimize the component of culture medium for the maximum cultivation of Candida sp. and Blastobotrys sp.
MATERIALS AND METHODS: Molasses and yeast extract were chosen as medium composition and Response Surface Methodology (RSM) was then employed to optimize the molasses and yeast extract.
RESULTS: Maximum growth of Candida sp. (7.63 log CFU mL-1) and Blastobotrys sp. (8.30 log CFU mL-1) were obtained from the fermentation. Optimum culture media for the growth of Candida sp., consist of 10% (w/v) molasses and 2% (w/v) yeast extract, while for Blastobotrys sp., were 1.94% (w/v) molasses and 2% (w/v) yeast extract.
CONCLUSION: This study shows that culture medium consists of molasses and yeast extract were able to produce maximum growth of Candida sp. and Blastobotrys sp., as a starter culture for cocoa bean fermentation.

Matched MeSH terms: Industrial Microbiology/methods*
Optimization of complex fermentation media for glucose oxidase production using statistical approach

Gunny AA, Arbain D, Sithamparam L

Pak J Biol Sci, 2013 Sep 15;16(18):960-4.
PMID: 24502155

Production cost of enzyme is largely determined by the type of the strain and raw material used to propagate the strain. Hence, selection of the strain and raw materials is crucial in enzyme production. For Glucose oxidase (GOx), previous studies showed Aspergillus terreus UniMAP AA-1 offers a better alternative to the existing sources. Thus, a lower production cost could be logically anticipated by growing the strain in a cheaper complex media such as molasses. In this work, sugar cane molasses, supplemented with urea and carbonate salt and a locally isolated strain Aspergillus terreus UniMAP AA-1 were used to produce a crude GOx enzyme in a small scale. A statistical optimization approach namely Response Surface Methodology (RSM) was used to optimize the media components for highest GOx activity. It was found that the highest GOx activity was achieved using a combination of molasses, carbonate salt and urea at concentration 32.51, 4.58 and 0.93% (w/v), respectively. This study provides an alternative optimized media conditions for GOx production using locally available raw materials.

Matched MeSH terms: Industrial Microbiology/methods*
Fulltext Enhanced cell disruption strategy in the release of recombinant hepatitis B surface antigen from Pichia pastoris using response surface methodology

Tam YJ, Allaudin ZN, Lila MA, Bahaman AR, Tan JS, Rezaei MA

BMC Biotechnol, 2012 Oct 05;12:70.
PMID: 23039947 DOI: 10.1186/1472-6750-12-70

BACKGROUND: Cell disruption strategies by high pressure homogenizer for the release of recombinant Hepatitis B surface antigen (HBsAg) from Pichia pastoris expression cells were optimized using response surface methodology (RSM) based on the central composite design (CCD). The factors studied include number of passes, biomass concentration and pulse pressure. Polynomial models were used to correlate the above mentioned factors to project the cell disruption capability and specific protein release of HBsAg from P. pastoris cells.
RESULTS: The proposed cell disruption strategy consisted of a number of passes set at 20 times, biomass concentration of 7.70 g/L of dry cell weight (DCW) and pulse pressure at 1,029 bar. The optimized cell disruption strategy was shown to increase cell disruption efficiency by 2-fold and 4-fold for specific protein release of HBsAg when compared to glass bead method yielding 75.68% cell disruption rate (CDR) and HBsAg concentration of 29.20 mg/L respectively.
CONCLUSIONS: The model equation generated from RSM on cell disruption of P. pastoris was found adequate to determine the significant factors and its interactions among the process variables and the optimum conditions in releasing HBsAg when validated against a glass bead cell disruption method. The findings from the study can open up a promising strategy for better recovery of HBsAg recombinant protein during downstream processing.

Matched MeSH terms: Industrial Microbiology/methods*
Zinc, magnesium, and calcium ion supplementation confers tolerance to acetic acid stress in industrial Saccharomyces cerevisiae utilizing xylose

Ismail KS, Sakamoto T, Hasunuma T, Zhao XQ, Kondo A

Biotechnol J, 2014 Dec;9(12):1519-25.
PMID: 24924214 DOI: 10.1002/biot.201300553

Lignocellulosic biomass is a potential substrate for ethanol production. However, pretreatment of lignocellulosic materials produces inhibitory compounds such as acetic acid, which negatively affect ethanol production by Saccharomyces cerevisiae. Supplementation of the medium with three metal ions (Zn(2+) , Mg(2+) , and Ca(2+) ) increased the tolerance of S. cerevisiae toward acetic acid compared to the absence of the ions. Ethanol production from xylose was most improved (by 34%) when the medium was supplemented with 2 mM Ca(2+) , followed by supplementation with 3.5 mM Mg(2+) (29% improvement), and 180 μM Zn(2+) (26% improvement). Higher ethanol production was linked to high cell viability in the presence of metal ions. Comparative transcriptomics between the supplemented cultures and the control suggested that improved cell viability resulted from the induction of genes controlling the cell wall and membrane. Only one gene, FIT2, was found to be up-regulated in common between the three metal ions. Also up-regulation of HXT1 and TKL1 might enhance xylose consumption in the presence of acetic acid. Thus, the addition of ionic nutrients is a simple and cost-effective method to improve the acetic acid tolerance of S. cerevisiae.

Matched MeSH terms: Industrial Microbiology/methods*
Influence of agitation speed on tannase production and morphology of Aspergillus niger FETL FT3 in submerged fermentation

Darah I, Sumathi G, Jain K, Lim SH

Appl Biochem Biotechnol, 2011 Dec;165(7-8):1682-90.
PMID: 21947762 DOI: 10.1007/s12010-011-9387-8

Agitation speed was found to influence the tannase production and fungal growth of Aspergillus niger FETL FT3. The optimal agitation speed was at 200 rpm which produced 1.41 U/ml tannase and 3.75 g/l of fungal growth. Lower or higher agitation speeds than 200 rpm produced lower enzyme production and fungal growth. Based on the SEM and TEM micrograph observation, there was a significant correlation between agitation speed and the morphology of the fungal mycelia. The results revealed an increase of the enzyme production with the change of the fungal growth morphology from filamentous to pelleted growth forms. However, the exposure to higher shear stress with an increasing agitation speed of the shaker also resulted in lower biomass yields as well as enzyme production.

Matched MeSH terms: Industrial Microbiology/methods*
Fulltext Biotechnological potential of Bacillus salmalaya 139SI: a novel strain for remediating water polluted with crude oil waste

Ismail S, Dadrasnia A

PLoS One, 2015;10(4):e0120931.
PMID: 25875763 DOI: 10.1371/journal.pone.0120931

Environmental contamination by petroleum hydrocarbons, mainly crude oil waste from refineries, is becoming prevalent worldwide. This study investigates the bioremediation of water contaminated with crude oil waste. Bacillus salamalaya 139SI, a bacterium isolated from a private farm soil in the Kuala Selangor in Malaysia, was found to be a potential degrader of crude oil waste. When a microbial population of 108 CFU ml-1 was used, the 139SI strain degraded 79% and 88% of the total petroleum hydrocarbons after 42 days of incubation in mineral salt media containing 2% and 1% of crude oil waste, respectively, under optimum conditions. In the uninoculated medium containing 1% crude oil waste, 6% was degraded. Relative to the control, the degradation was significantly greater when a bacteria count of 99 × 108 CFU ml-1 was added to the treatments polluted with 1% oil. Thus, this isolated strain is useful for enhancing the biotreatment of oil in wastewater.

Matched MeSH terms: Industrial Microbiology/methods*