Bacillus subtilis Contributes to Amylase Production in the Honey Sac of Apis mellifera
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College of Food Science and Technology, Yunnan Agricultural University, Kunming 650201, China
2
Faculty of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China
*
Author to whom correspondence should be addressed.
Insects 2025, 16(2), 221; https://doi.org/10.3390/insects16020221
Submission received: 10 December 2024
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Revised: 13 February 2025
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Accepted: 16 February 2025
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Published: 18 February 2025
(This article belongs to the Section Social Insects and Apiculture)
Simple Summary
Amylase values in honey serve as a definitive biomarker for assessing the freshness of honey, with its concentration being a critical parameter for determining compliance with product standards. Bacillus subtilis contributes to amylase levels in honey sac fluid and honey, in addition to Apis mellifera secretion. Amylase activity in honey sac fluid exceeds nectar values, with the presence of B. subtilis correlating with higher amylase levels. In vitro experiments confirm B. subtilis amylase production in the presence of sucrose or honey sac fluid. Bacterial counts peak at 105 CFU/mL in the honey sac, indicating a significant role in amylase synthesis. This study establishes a novel methodology for the analysis of bacterial amylase in honey, which may improve honey quality assessment. This discovery has important implications for the standardization and quality assessment of honey, suggesting that future regulations and freshness indicators should account for the role of microflora in addition to traditional measures.
Abstract
Background: Amylase activity is a critical biomarker for assessing the freshness of honey. Historically, bees have been considered the sole source of honey amylase. However, recent studies suggest that Bacillus subtilis may also contribute to amylase production in the honey sac of Apis mellifera. Methods: In this study, amylase levels were measured in samples of nectar, honey sac fluid, and honey. The identification of B. subtilis in nectar, honey sac, and honey was evaluated. An in vitro bacterial culture system and a feeding experiment were developed to simulate honey sac conditions. Results: Our results showed that B. subtilis was detected in all sample groups, with the highest concentration in honey sac samples. Amylase levels in honey sac and honey samples were significantly higher than those in nectar. In the simulation experiment, amylase activity was only observed in cultures containing both B. subtilis and sucrose/nectar; no activity was detected in cultures containing only H2O or no B. subtilis. In the feeding experiment, bees fed sucrose or nectar showed higher amylase activity in their honey sacs than those fed water. Conclusions: Our data show that B. subtilis can produce amylase and offer potential for more standardized quality assessment of honey.
