IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Sodium gluconate and calcium gluconate methods are important techniques available for gluconic acid fermentation. The comparative analysis of these fermentations has been addressed using Aspergillus niger. The techniques are equally influenced by the spores age in slant growth, inoculum level in germination and production media, different levels of Fe, Cu, Zn and Mn. Sodium gluconate method is promising with respect to lesser time for slant age (3 d) and lesser time of fermentation (6 d) compared to the calcium gluconate method (slant age - 6 d, and time of fermentation - 7 d). © 1993 Springer-Verlag.

GENERAL

Department Of Chemical Engineering

Bioprocess Engineering

Comparative analysis of calcium gluconate and sodium gluconate techniques for the production of gluconic acid by Aspergillus niger

Important parameters in the regeneration of protoplasts are viability, the capacity to synthesize cell walls and the retention of properties of the parent cell. Mycelial protoplasts of Trichoderma longibrachiatum (Trichoderma reesei) have been regenerated. Factors influencing the regeneration of protoplasts of T. longibrachiatum QM 9414 were found to be, the nature of osmotic stabilizer, the concentration of osmotic stabilizer, pH, temperature, and the composition of regeneration medium. With glucose-mineral regeneration medium, the optimum conditions for protoplasts regeneration were 0.5 M KCl, pH 6.0 and temperature 30°C. With Czapek-Dox medium, the optimum conditions were 0.7 M mannitol, pH 6.0 and temperature 30°C. Maximum regeneration frequency of T. longibrachiatum protoplasts were obtained using glucose-mineral medium. © 1993 Springer-Verlag.

Improved technique on reversion of mycelial protoplast of Trichoderma reesei into mycelia

Efficient synthesis of large numbers of viable sphaeroplast from Saccharomyces cerevisiae has been found to be influenced by a number of factors. In this case, Trichoderma harzianum, NCIM 1185, culture filtrate has been used to prepare sphaeroplast from Saccharomyces cerevisiae, NCIM 3288. A method has been devised to isolate large number of viable sphaeroplast from the cell. Detailed analysis of various factors affecting the formation of sphaeroplasts from Saccharomyces cerevisiae has not yet been reported. This study showed critical analysis of various factors which influenced sphaeroplast formation. Most suitable conditions were: Age of the organism in slant - 1 d, cell age in liquid medium - 24 h, time of incubation of cell with 0.3% β-mercaptoethanol - 30 min, level of lytic ezyme concentration - 79.2 ml, concentration of cell (dry wt. equivalent) - 0.1262 g, time of contact with lytic enzyme - 25 min, temperature of sphaeroplast formation - 30 °C, phosphate buffer - 25 mM of pH 6.5 and KCl as osmotic stabilizer - 0.7 M. © 1992 Springer-Verlag.

Critical analysis of factors influencing sphaeroplast generation from Saccharomyces cerevisiae

Efficient synthesis of a large number of viable protoplasts from Trichoderma longibrachiatum (Trichoderma reesei) mycelium has been found to be influenced by a number of factors. In this case, Trichoderma harzianum NCIM 1185 culture filtrate has been used to prepare protoplasts from Trichoderma longibrachiatum QM 9414. A method has been devised to isolate a large number of viable protoplasts from the mycelium. Detailed analysis of different factors affecting the synthesis of protoplasts from T. longibrachiatum has not yet been reported. The most suitable conditions for protoplasting were as follows: age of the organism in slant, 3 days; mycelium age, 20 h; volume of lytic enzymes, 190 ml; mycelial weight (dry equivalent), 1.66 g; time of contact with lytic enzymes, 2 h; temperature of protoplasting, 30°C; phosphate buffer, 25 mm, pH 6.5; KCl as osmotic stabilizer, 0.7 m. Proper spreading of the mycelium in contact with the lytic enzymes was also found to be necessary. © 1992.

Enzyme and Microbial Technology

Studies on critical analysis of factors influencing improved production of protoplasts from Trichoderma reesei mycelium

A method for catalyst development has been suggested for immobilizing whole E. coli cells containing penicillin amidase. Conventional methods have limitations, such as permeation of substrate and product through cellular membranes, leaching of protein and other cellular components into the reaction phase, lower specific activity compared to immobilized enzyme system, etc. The whole cell immobilization technique has been optimized for different process parameters. The most suitable conditions for this process were pH, 4.25; cell concentration, 3.75%; concentration of glutaraldehyde, 1.5%; level of bovine serum albumin as additional support, 2 mg ml-1. The reaction was continued for 2 h. The granular catalyst has good mechanical strength, low protein leachability, and high retention of penicillin amidase activity. © 1991.

Studies on improved techniques for immobilizing and stabilizing penicillin amidase associated with E. coli cells

To obtain a catalyst with good mechanical stress stability and other operational characteristics, cross-linked aggregates of whole Escherichia coli containing penicillin amidase were reinforced with surface modified precipitated silica and chitosan. The immobilized cells plus mixed fillers possess better performance characteristics i.e. higher stability at 4°C and 30°C, least protein leaching capacity and good settling characteristics. Most suitable conditions to prepare catalyst with mixed fillers were: chitosan, 0.3: silica, 0.2 g/g d.wt cell; and minimum moisture content in catalyst, 30% (w/w). © 1991 Chapman & Hall.

Biotechnology Techniques

Immobilization of whole Escherichia coli containing penicillin amidase using cross-linking agents and fillers

In general in any fermentation the volume of wastewater is too high. The excess water might be utilized to reduce consumption of process water. In this investigation cell-free culture filtrate was used instead of process water. In batch experiments, cell-free culture filtrate was used in ratios between 0·1 and 1·0 for eight subsequent batches. The specific growth rate was higher than that of the first batch for reusability ratios between 0·1 and 0·8 in all batches. Synthesis of penicillin amidase was found to be more suitable in the fourth batch with a recycle ratio between 0·6 and 1·0. An extracellular protein factor was found to influence the synthesis of penicillin amidase. © 1991.

Process Biochemistry

Effect of recycling of fermentation broth for the production of penicillin amidase

For improved biosynthesis of penicillin amidase by E. coli, NCIM 2400, the participation of different carboxylic acids and polyols has been studied in association with the effect of phenylacetic acid. A modified defined medium has been devised for this purpose. © 1991 Springer-Verlag.

The role of phenylacetic acid in biosynthesis of penicillin amidase in E. coli

The level of α-mannanase in mixed fungal culture of Trichoderma reesei, D1-6, and Aspergillus wentii, Pt 2804, affects the extracellular activities of cellulase. The endoglucanase component of the cellulase system is a glycoprotein having mannose and other sugars and sugaramines in its glycan moiety. Its activity is inhibited by α-mannanase. The inactivation of endoglucanase by α-mannanase can be prevented by galactose. © 1990 Springer-Verlag.

Endoglucanase from the mixed culture of Trichoderma reesei and Aspergillus wentii

The rate of total extracellular xylanase production in Trichoderma reesei, QM 9414, system was affected by temperature and pH. In vitro studies with xylanase showed different temperature optima for activity in presence and in absence of xylan as substrate. Similar behaviour was observed in the pH studies. A number of temperature and pH optima also suggested the multiple nature of xyalanase. © 1989 Springer-Verlag.

Multiple pH and temperature optimum of extracellular xylanase from Trichoderma reesei QM 9414

Tween surfactants (Tween 20, 40, 60 and 80) stimulated the excretion of protein by Trichoderma reesei QM9414 during growth on cellulose. Tween 60 gave maximal secretion of protein. The presence of Tween decreased the lag time of growth and weakly stimulated growth. Almost the same proportion of cell-wall-bound activity was found in cultures supplemented with Tween for β-glucosidase, acid phosphatase and β-N-acetyl-glucosaminidase. The addition of various Tweens (20, 40, 60 or 80) had only a small effect on the fatty acid composition of the mycelium of T. reesei. Among 5 mutant strains with different secretory capacity, all but one showed stimulation of protein secretion by Tween surfactants. There was no observable correlation between the stimulation of secretion by Tween and the degree of unsaturation of mycelial fatty acids. It is concluded that the stimulation of protein secretion by Tween surfactants does not involve release of surface bound enzymes or changes in membrane fatty acid unsaturation. © 1987.

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FEMS Microbiology Letters

Stimulation of protein secretion in Trichoderma reesei by Tween surfactants is not correlated with changes in enzyme localization or membrane fatty acid composition

A significant increase in extracellular xylanase activity was observed in the mixed culture fermentation of Trichoderma reesei D1‐6 and Aspergillus wentii Pt 2804 when A. wentii inoculation was phased by 15 h. A. wentii produced a polysaccharide, chiefly consisting of glucose monomeric units, which was required for expression of maximum xylanase activity. Expression of high activity of xylanase in the A. wentii phased mixed culture compared to that in either T. reesei or A. wentii single cultures appeared to be controlled by the combined action of a polysaccharide produced by A. wentii and the relative growth of the two fungi in the mixed culture. Copyright © 1987 John Wiley & Sons, Inc.

Biotechnology and Bioengineering

Effect of culture phasing and a polysaccharide on production of xylanase by mixed culture of trichoderma reesei D1‐6 and aspergillus wentii Pt 2804

Significant increase in extracellular cellulase and hemicellulase activities was observed in the biosynthesis of cellulase enzyme in mixed culture fermentation of Trichoderma reesei D 1–6 and Aspergillus wentii Pt 2804 when the A. wentii inoculation was phased by 15 h. The optimal conditions of fermentation by the mixed culture have been established. Presence of mannanase has been found to affect the release as well as activity of cellulase enzyme produced in mixed culture. Copyright © 1985 John Wiley & Sons, Inc.

Effect of culture phasing and mannanase on production of cellulase and hemicellulase by mixed culture of Trichoderma reesei D 1–6 and Aspergillus wentii pt 2804

Surface culture citric acid fermentation was carried out by Aspergillus niger T55, a strain isolated from its natural source, using cane molasses, either untreated or treated by various methods. Citric acid biosynthesis is seriously impaired by both organic and inorganic inhibitors. A combined treatment of molasses with tricalcium phosphate, hydrochloric acid, and Sephadex fractionation minimizes the level of inorganic and organic inhibitors in molasses and increases the production of citric acid (65% weight yield based on total reducing sugar). The optimum level of individual metal ions for citric acid production depends on the concentration of other metals in the medium. Copyright © 1984 John Wiley & Sons, Inc.

Pretreatment of indian cane molasses for increased production of citric acid

Biotechnology Letters

Studies on mixed fungal culture for cellulase and hemi-cellulase production part-1: Optimization of medium for the mixed culture of Trichoderma reesei D1-6 and Aspergillus Pt 2804