Zinc solubilizing ability of Bacillus sp. and Pseudomonas sp. was assessed using zinc oxide, zinc sulphide (sphalerite) and zinc carbonate in both plate and broth assays. ZSB-O-1 (Bacillus sp.) showed highest dissolution in the zinc sulphide (Sphalerite ore), with 2.80 cm of dissolution zone and 14.50 cm 2 of area in the plate assay and 13.60 mg kg -1 of zinc in the broth assay on the 15 th day after inoculation. The ZSB-S-2 (Pseudomonas sp.) showed more solubilizing ability in the zinc oxide, with 3.30 cm clearing zone and 20.43 cm 2 area in the plate assay and 16.40 mg kg -1 of zinc in the broth assay over the same inoculation period. The isolate ZSB-S-4 (Pseudomonas sp.) has highest solubilizing potential in zinc carbonate with 6.20 cm of dissolution zone and 13.40 cm 2 area in the plate assay and 13.40 mg kg -1 of zinc in the broth assay. Thus, the solubilization potential varies among different cultures. The solubilization might be due to production of acids by the culture, since the pH of the culture broth has been shifted form 7.0-7.3 to 4.8-6.5 after 15 days of inoculation. The zinc tolerance limit for two cultures (ZSB-O-1 and ZSB-S-2) was studied and determined to be upto 100 mg kg -1 of zinc in the in vitro broth assay.

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f i e enzymes amylase, protease, phosphatase and P-glucosidase in rough rice @addy) were activated during the soaking step of parboiling. l%e extent of activation of these enzymes varied with the soaking duration and the parboiling methods adopted. Highest activities were observed in the cold soaking method followed by the double steaming and household methods. P-Glucosidase activity was eliminated in the presteaming stage of the double steaming process. Hot soaking inactivated all these enzymes. l%e steam in the parboiling process inactivated the enzymes partly while the pressure parboiling process inactivated them totally. Studies with pur@ied enzymes also revealed the activation of enzymes during soaking. Enzyme activity contributes to the loss of solids during soaking and also to the characteristic odor of parboiled rice.

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