The fermentation of whey by Kluyveromyces marxianus strain MTCC 1288 was studied using varying lactose concentrations at constant temperature and pH. The increase in substrate concentration up to a certain limit was accompanied by an increase in ethanol formation, for example, at a substrate concentration of 10 g L )1 , the production of ethanol was 0.618 g L )1 whereas at 50 g L )1 it was 3.98 g L )1 . However, an increase in lactose concentration to 100 g L )1 led to a drastic decrease in product formation and substrate utilization. The maximum ethanol yield was obtained with an initial lactose concentration of 50 g L )1 . A method of batch kinetics was utilized to formulate a mathematical model using substrate and product inhibition constants. The model successfully simulated the batch kinetics observed at S 0 ¼ 10 and 50 g L )1 but failed in case of S 0 ¼ 100 g L )1 because of strong substrate inhibition.

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This research article reports the computational analysis of temperature distribution in microwave-heated convenience food such as potato. The detailed study of temperature (because temperature is a function of bacterial inactivation) and microwave powers along with drying time for the preservation of food material has been presented. Therefore, a mathematical model for potato sample is developed to predict the behavior of temperature distribution at each possible point and different shapes (slab, cylindrical, and spherical) of food material. The developed mathematical model is programmed by MATLAB software. Another parameter, microwave power is also a function of temperature. The ranging values of various microwave powers (125 W, 375 W, 625 W, 875 W, and 1250 W) along with different values of drying time (0 to 10 minutes) have been used for computation. The obtained results show the uniformity of temperature distribution throughout the whole product in the form of a three-dimensional structure. The model provides the minimum and maximum temperature ranges in specimens without performing an experiment which depicts the condition of bacterial inactivation.

A huge amount of used lubricating oils are produced worldwide. The different sources of used lubricating oils are railway workshops, industries, ship garages, defense machinery, automobiles workshops, etc. All types of lubricating oils in service in automobiles and process industries become contaminated and lose their performance due to changes in some of their properties. Therefore, such oils must be removed as used oil from the service as frequently as necessary. How to handle and what to do with the used lubricating oils are serious concerns to environmentalists, governments, industries and research scientists. Used lubricating oil disposal techniques of the past such as land filling, road oiling, and track side foliage control, indiscriminate dumping, burning for energy, etc., create serious environmental problems. Many of these disposal techniques are severely restricted by current state and federal environmental regulations 1. The common disposal technique of used lubricating oil is burning for generation of energy. Burning and all other routes of disposals of used lubricating oils are uneconomical and result

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