How should negative OD readings be processed in DNS assay for reducing sugar?

Sometimes I get negative OD readings (at 540 nm) when determining reducing sugars using glucose as standard (Miller, 1959). When I use Microsoft Excel to plot the glucose standard curve, the line...

03 April 2015 4,525 15 View

Why does the specific activity of my enzyme decrease at each step of purification?

Can anyone provide possible reasons why the specific activity of my cellulase (from bacteria) keeps reducing after each step of purification? So far, the crude enzyme has the highest activity...

11 December 2014 8,944 34 View

Why is enzyme not precipitating even at 90% ammonium sulphate saturation?

I am trying to precipitate a bacterial cellulase produced on a lignocellulosic hydrolysate as the first step in the purification of the enzyme. I did step-wise ammonium sulphate fractionation at...

07 August 2014 4,331 18 View

What is the most suitable column to analyze the composition of lignocellulosic hydrolysate using LCMS?

The use of HPLC might give some unknown peaks. However, LCMS would allow a more detailed identification of the compounds in the hydrolysate. Such compounds might include sugars (monomers and...

07 August 2014 5,385 4 View

Is it compulsory to deduct OD readings of enzyme blanks in cellulase assays?

One of the most cited references regarding cellulase (saccharifying cellulase, endo-, exo- and betaglucosidase) assays (Ghose, 1987 & Wood and Bhat, 1988) recommend that OD readings of enzyme...

03 April 2014 6,141 1 View

Conflict between BIOLOG and 16S rRNA sequence BLAST in identifying a bacterial strain?

A bacterium was identified by BIOLOG as a particular species; running a BLAST search on the 16S rRNA sequence of the same organism gave a different specie of the same genus. The one with the...

31 December 2013 1,706 28 View

Can someone advise on the enzyme concentration to release 2 mg glucose in cellulase filter paper assay?

The IUPAC procedure for determining total cellulase activity using filter paper states that one should prepare two dilutions of the enzyme such that one dilution will release > 2 mg glucose from...

10 November 2013 3,109 5 View

How to perform life cycle analysis (LCA)?

I wish to know how to perform life cycle analysis or assessment (LCA) of any biotechnological processes especially for biofuels. What are the basic things to consider? Is there any book or...

08 September 2013 7,831 3 View

Does keeping of broth samples at -20degC affect cfu, OD and enzyme activity readings?

In running an experiment to plot growth curve of an organism which is growing on a cellulosic substrate, it is necessary to collect samples from the shake flask at intervals (2-4 hours over 72...

06 July 2013 7,926 10 View

Tips on Writing Review Article

What are the important guidelines for one who wishes to write a review article for publication in a reputable journal for the first time?

03 April 2013 4,567 13 View

error in running a model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

error in modelling model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

MGL tools

20 June 2021 0 0 View

what is the simplest definition of ion exchange capacity

What this unit identifies for the ion exchange capacity ca. 0.92 meq. g-1. I am a newcomer in the membrane area. I just started. I highly appreciate your help

08 May 2021 0 0 View

what is the simplest definition of ion exchange capacity

What this unit identifies for the ion exchange capacity ca. 0.92 meq. g-1. I am a newcomer in the membrane area. I just started. I highly appreciate your help

08 May 2021 0 0 View

i have some problem with chtMultiRegionSimpleFoam

--> FOAM FATAL ERROR: Maximum number of iterations exceeded From function Foam::scalar Foam::species::thermo::T(Foam::scalar, Foam::scalar, Foam::scalar, Foam::scalar (Foam::species::thermo::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo::*)(Foam::scalar) const) const [with Thermo = Foam::hConstThermo >; Type = Foam::sensibleEnthalpy; Foam::scalar = double; Foam::species::thermo = Foam::species::thermo >, Foam::sensibleEnthalpy>] in file /home/ubuntu/OpenFOAM/OpenFOAM-4.1/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 66. FOAM aborting #0 Foam::error::printStack(Foam::Ostream&) at ??:? #1 Foam::error::abort() at ??:? #2 Foam::heRhoThermo >, Foam::sensibleEnthalpy> > > >::calculate() at ??:? #3 Foam::heRhoThermo >, Foam::sensibleEnthalpy> > > >::correct() at ??:? #4 ? at ??:? #5 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6" #6 ? at ??:?

24 March 2021 0 0 View

Can we classify HV and LV lines based on line length?

I have dataset which shows the length of power lines. I need to classify the lines based on the line length. Is there a rule to classify the High voltage (HV) and low voltage (LV) lines based on...

03 March 2021 4,116 4 View

What is the production process of CaFe ferroalloys?

I looking for ferro calcium production process

03 March 2021 1,755 4 View

Resistor definition in Piezoelectric bimorph with ANSYS workbench

Hello, good day! I am trying to simulate similar bimorph piezoelectric harvester with below commands. However, the output power doesn't change with resistor value. Please help to find the reason. ET,10,CIRCU94,0 !SET UP RESISTOR R,1,100000 !RESISTANCE VALUE TYPE,10 !SET ELEMENT TYPE E,1,2 !CREATE RESISTOR BETWEEN NODES 1 AND 2 Thanks in advance Regards,

02 March 2021 0 0 View

How to quantitative analize the data of TNBS assay for gelatin?

Estemeed colleagues, I found some issues regarding the quantification of the data for TNBS assay. There are different protocols on how to perform that but it is clear to me the "fil rouge" that...

02 March 2021 2,616 1 View