Numbi Ramudu Kamini

Lipase production from Aspergillus niger by solid-state fermentation using gingelly oil cake

Cultural conditions for the production of lipase by Aspergillus niger strain MTCC 2594 by solid-state fermentation using gingelly oil cake were standardized. A lipase activity of 363·6 U/g of dry substrate was obtained at 72 h under optimum conditions. Addition of various nitrogen sources, carbohydrates and inducers to the substrate was found to be ineffective. The enzyme was optimally active at pH 7·0 and 37°C, and was found to be stable between pH 4·0–10·0 and 4–50°C. The enzyme also showed remarkable stability in the presence of detergents and it could be effectively used for the removal of triglyceride soils in laundry.

Cutinase-Like Enzyme from the Yeast Cryptococcus sp. Strain S-2 Hydrolyzes Polylactic Acid and Other Biodegradable Plastics

ABSTRACT A purified lipase from the yeast Cryptococcus sp. strain S-2 exhibited remote homology to proteins belonging to the cutinase family rather than to lipases. This enzyme could effectively degrade the high-molecular-weight compound polylactic acid, as well as other biodegradable plastics, including polybutylene succinate, poly (ε-caprolactone), and poly(3-hydroxybutyrate).

Microbial degradation of aliphatic and aliphatic-aromatic co-polyesters.

Biodegradable plastics (BPs) have attracted much attention since more than a decade because they can easily be degraded by microorganisms in the environment. The development of aliphatic-aromatic co-polyesters has combined excellent mechanical properties with biodegradability and an ideal replacement for the conventional nondegradable thermoplastics. The microorganisms degrading these polyesters are widely distributed in various environments. Although various aliphatic, aromatic, and aliphatic-aromatic co-polyester-degrading microorganisms and their enzymes have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. In this review, we have reported some new microorganisms and their enzymes which could degrade various aliphatic, aromatic, as well as aliphatic-aromatic co-polyesters like poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), poly(ε-caprolactone) (PCL), poly(ethylene succinate) (PES), poly(l-lactic acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-hydroxyvalterate) (PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-terephthalate) (PBST), and poly(butylene succinate/terephthalate/isophthalate)-co-(lactate) (PBSTIL). The mechanism of degradation of aliphatic as well as aliphatic-aromatic co-polyesters has also been discussed. The degradation ability of microorganisms against various polyesters might be useful for the treatment and recycling of biodegradable wastes or bioremediation of the polyester-contaminated environments.

Potentiometric biosensor for determination of urea in milk using immobilized Arthrobacter creatinolyticus urease.

The extracellular urease from Arthrobacter creatinolyticus was partially purified by ammonium sulfate precipitation and immobilized on PAN [poly(acrylonitrile-methylmethacrylate-sodium vinylsulfonate)] membrane. The urease immobilized PAN membrane exhibited an activity of 97.92U/cm(2) under the optimum conditions of 1.0% enzyme concentration, 15% glutaraldehyde, 24h immobilization time and temperature of 4°C. The changes in surface morphology of the membrane after immobilization were studied by SEM and ATR-FTIR analysis. Immobilized membrane was associated with potentiometric electrode for calibration of biosensor and the results showed a linear response for wide range of urea concentration from 1 to 100mM. The immobilized urease had good storage stability for a period of 70days at 4°C and could be effectively reused for 13cycles. Urease immobilized membrane was also employed in analysis of urea spiked milk samples.

Wealth from waste – beef extract for microbiological media from tannery solid waste

Lime fleshing waste is one of the major hazardous solid wastes from leather industry. Utilization of the waste is one of the appropriate strategies to address the environmental issues and to realize economical returns. A process of preparation of beef extract from limed fleshing waste has been developed. The beef extract prepared is intended for microbial application. According to the process developed, the alkalis present in the fleshing waste were neutralized and removed by washing. Then the fleshing waste was hydrolyzed thermally and the hydrolysate obtained was lyophilized. The prepared product was characterized. The characteristics of the prepared product were compared with those of a widely accepted market product (Hi-Media). The beef extract prepared was found to be in compliance with all the requirements of the relevant standard. The product was also found to perform similarly to Hi-Media beef extract. The chemistry of the product was studied using tools such as FT-IR, HPLC, Maldi-TOF, 13C NMR and 1H NMR. The product chemistry was found to be akin to that of the beef extract of Hi-Media.

Screening and production of a potent extracellular Arthrobacter creatinolyticus urease for determination of heavy metal ions

This paper describes the isolation of a potent extracellular urease producing microorganism, identified by 16S rRNA as Arthrobacter creatinolyticus MTCC 5604 and its medium optimization by classical one‐factor‐at‐a‐time method and central composite rotatable design (CCRD), a tool of response surface methodology (RSM). An optimal activity of 9.0 U ml−1 was obtained by classical method and statistical optimization of the medium resulted in an activity of 17.35 U ml−1 at 48 h and 30 °C. This activity was 4.91 times greater than the initial activity (3.53 U ml−1) from the basal medium and the enzyme showed maximum activity at pH 8.0 and 60 °C and was stable at pH 7.0–9.0 and temperatures up to 50 °C. Furthermore, the enzyme was assessed for its activity reduction by determining the inhibitory concentration (IC50) of heavy metal ions and the inhibition of urease was in the order of Cu(II) > Cd(II) > Zn(II) > Ni(II). Urease was highly sensitive to Cu(II) and its inhibition was 94% and 100% in model solutions containing a mixture of Cu(II) with heavy metal ions Cd(II) and Zn(II), respectively. The results of these studies suggested that the enzyme could be utilized as sensors to determine the levels of Cu(II) ions in industrial effluents, contaminated soil and ground water.

Inexpensive α-amylase production and application for fiber splitting in leather processing

Recently, the production of superior quality enzymes using waste sources has promoted greater research interest due to their enhanced enzyme activity, selectivity and stability. In this work, the production of enzyme α-amylase from wheat bran using a solid-state fermentation technique is presented. Further, reasonably high production of liquid α-amylase was achieved with enhanced activity and stability. In order to check the benefits of α-amylase, a fiber opening process using an in-house α-amylase has been developed for goatskins, in an attempt to reduce pollution from beam house processes, while doing a cost and environment benefit analysis. In addition, the effect of fiber opening by the developed enzyme was compared with a couple of commercial enzyme products and chemical processes (lime and sodium sulphide). After the fiber splitting process, the pelt was made into crust leather and the effect of fiber splitting on the strength properties related morphological changes of the crust leather samples were thoroughly investigated. The findings revealed that the inexpensive enzyme produced in this study displayed lower pollution load (COD, TS), with significant release of inter-fibrillary materials. Another significant observation was that the enzyme concentrate from the SSF process showed equivalent fiber splitting with lower cost than chemical-based processes and the commercially used powder enzyme products. Finally the developed inexpensive enzyme will act as a better replacement for chemical processes with lower cost.

PROCESS STRATEGIES FOR ALKALINE LIPASE PRODUCTION USING Aspergillus Niger MTCC 2594

We report scale-up production of alkaline lipases from Aspergillus niger MTCC 2594 using submerged stir tank fermenter (SSTF). The batch culture experiments and biomass studies suggest that olive oil used in the process reduced enzyme yield. We found that the addition of olive oil intermittently might be a potential fed-batch strategy to improve lipase production using Aspergillus niger MTCC 2594.

A novel synthetic peptide derivative from lactoferrin exhibiting antimicrobial activity.

A tetrapeptide derivative Boc‐l‐Lys(Boc)‐l‐Arg‐l‐Asp‐l‐Ser(But)‐OBut (PEP 1261; Boc is butoxycarbonyl, But is t‐butyl and OBut is t‐butyl ester), synthesized by a solution‐phase strategy, exhibited antimicrobial activity against a broad spectrum of micro‐organisms at an optimal concentration of 500 μg/ml. Whereas the tetrapeptide salt (l‐Lys‐l‐Arg‐l‐Asp‐l‐Ser·HCl) was found to be fairly effective against bacterial cultures, it was not effective against fungal cultures. Comparative growth studies showed that PEP 1261 was equally as potent as the conventional antibiotics kanamycin, streptomycin and actidione for the Gram‐negative bacteria Escherichia coli, Pseudomonas alcaligenes and the non‐filamentous fungus Saccharomyces cerevisiae (bakers yeast), whereas 62 and 88.9% inhibition were observed for Gram‐positive organisms such as Staphylococcus aureus and Bacillus thuringiensis respectively. PEP 1261 might exert its antimicrobial activity by permeabilizing the bacterial membrane, and this was confirmed by an increase in β‐galactosidase activity.