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a b s t r a c tWhole cell lipase catalysis and microalgal feedstocks make overall biodiesel synthesis greener and sustainable. In this study, a novel approach of whole cell lipase-catalyzed conversion of Scenedesmus obliquus lipids was investigated for biodiesel synthesis. Microalgal biodiesel was characterized for its fuel properties. Optimization of process parameters for immobilized Aspergillus niger whole cell lipasecatalyzed biodiesel synthesis was carried out. Highest biodiesel conversion of 53.76% was achieved from S. obliquus lipids at 35 C, methanol to oil ratio of 5:1 and 2.5% water content based on oil weight with 6 BSPs (Biomass support particles).Step-wise methanol addition was applied to account for methanol tolerance, which improved biodiesel conversion upto 80.97% and gave 90.82 ± 1.43% yield. Immobilized A. niger lipase can be used for 2 batches without significant loss in conversion efficiency. Most of the fuel properties of biodiesel met the specifications set by international standards.

Patulin is a mycotoxin produced by a number of molds involved in fruit spoilage. This compound is carcinogenic and teratogenic. Various methods are currently used to reduce the levels of patulin in apple juice, namely, charcoal treatment, chemical preservation (sulfur dioxide), gamma irradiation, fermentation, and trimming of fungus-infected apples. Many of these processes are expensive and time-consuming. Therefore, there is a need to find a convenient and economical process to control patulin levels. This study was undertaken to evaluate the effectiveness of several clarification processes for the reduction of patulin. Clarification was carried out on a laboratory scale. Apple pulp was spiked with patulin, pressed, and clarified using four different processes, namely, fining with bentonite, enzyme (pectinase) treatment, paper filtration, and centrifugation. Patulin was recovered from the clarified juice by liquid-liquid extraction, and solid-phase chromatography was used for sample clean-up prior to analysis by high-performance liquid chromatography (HPLC). The minimum detectable limit using HPLC was 20 microg/liter. Pressing followed by centrifugation resulted in an average toxin reduction of 89%. Total toxin reduction using filtration, enzyme treatment, and fining were 70, 73, and 77%, respectively. Patulin reduction was due to the binding of the toxin to solid substrates that was verified by analyzing the clarified juice as well as the filter cake, pellet, and sediment. The combined concentrations correlated to the spiked concentration. These results reveal that clarification was successful in the reduction of patulin levels in apple juice. However, clarification resulted in high levels of patulin in the pressed pulp after filtration and centrifugation, and this could be harmful if they are used as animal feeds.

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Aims:  To access inulinase production by Xanthomonas campestris pv phaseoli using the submerged and solid state cultivation (SSC) methods. Methods and Results:  Various carbon sources, inulin‐rich solid substrates and pure synthetic inulin were tested for their efficiency in inulinase induction. The highest inulinase production (17·42 IU ml−1) in submerged cultures of X. campestris was observed with inulin as a carbon source with an initial pH, temperature and agitation of 7·0, 37°C and 150 rev min−1 respectively. Among the various substrates, garlic peels (117 IU gds−1) and onion peels (101 IU gds−1) were found to be the best for inulinase production. Conclusion:  The inulinase production level of X. campestris was 6·7‐fold higher in garlic and 5·8‐fold in onion, under optimized SSC conditions compared with the submerged culture. Significance and Impact of the Study:  This is the first report on inulinase production from garlic and onion peels by X. campestris using SSC. SSC is an efficient method for inulinase production by X. campestris for commercial applications.

The combined effect of simultaneous saccharification and fermentation and separate hydrolysis and fermentation (SHF) for ethanol production by Kluyveromyces marxianus 6556 was studied using two lignocellulosic feedstocks viz., corncob and soybean cake. The ethanologenic efficiency of K. marxianus 6556 was observed as 28% (theoretical yield) in a fermentation medium containing glucose, but, there was no ethanol production by cells grown on xylose. A maximum sugar release of 888 mg/g corncob and 552 mg/g soybean cake was achieved through acid hydrolysis pretreatment. Furthermore, corncob and soybean cake treated with commercial cellulase (100 IU for 48 h) from Trichoderma reesei yielded reducing sugars of 205 and 100 mg/g, respectively. Simultaneous saccharification and fermentation resulted in highest ethanol production of 5.68 g/l on corncob and 2.14 g/l on soybean cake after 48 h of incubation. On the contrary, the presence of inhibitors decreased the overall ethanol yield in the hydrolysates obtained through SHF of corncob and soybean cake.